Science suggests our brains aren’t fully developed until roughly age 25. It’s no surprise, then, that the early 20s are known for stumbles and mishaps while we find our footing in adulthood.

Naomi Osaka’s story doesn’t fit the mold. At 21, she’s the No. 1 tennis player in the world. Osaka, who has a Japanese mother and a Haitian father, plays for Japan; she won two consecutive Grand Slam singles titles, in 2018 and 2019. She is the first player representing Japan to make it to the top of the Women’s Tennis Association (WTA) or the Association of Tennis Professionals (ATP) rankings, according to the Associated Press.

Earlier this month, Barbie named Osaka one of its global role models as part of the brand’s 60th anniversary celebrations and its Dream Gap Project to empower girls.

The Lily chatted with Osaka about role models, her definition of happiness, and rice, among other subjects.

This interview has been lightly edited and condensed for clarity.

The Lily: Barbie is honoring you as a boundary-breaking role model for girls. What lessons do you hope girls take away from watching your career?

Naomi Osaka: I hope that girls get inspired when they watch me play. I think that having role models is really important growing up and I can only hope that maybe one day a little girl looks at me playing tennis and she wishes that she can be a tennis player, too. And I think that that’s one of the best things that I could possibly do in life. So, I think that’s my biggest hope.

TL: Who are your role models — both in the sports world and outside of it?

NO: My biggest role model is my mom. I saw everything that she was sacrificing to get me in this position and I always wanted to do well for her. And then, of course, Serena [Williams]. Beyoncé. I really like Usain Bolt, too.

TL: At 21, you’ve already accomplished so much, which is powerful for girls to see. But massive success comes with significant expectations — from sponsors, from fans. How do you navigate the weight of others’ expectations in your career?

NO: I feel like I’m old, but I’m young at the same time, because I’ve been on the tour for a bit. This is my third year, maybe, being fully on the tour, and I feel like I’ve adjusted to that sort of pressure a while ago, and I think the only thing now is pressure from myself, because I’m a bit of a perfectionist. I try to enjoy my time more. There’s people that actually come out to watch me play specifically, so I just hope that I can do well and hope that they enjoy the match that they’re watching.

TL: You’re currently No. 1 in the WTA rankings. What does that feel like, to be ranked the best women’s tennis player in the world?

NO: I haven’t really thought about it too much, because we kind of move tournament from tournament. It’s really amazing, I think. When you’re little you always want to be No. 1, and to finally be here and see that all your hard work has paid off — it’s definitely an incredible feeling.

TL: How would you describe your personality off the court versus on the court? Who is Naomi behind the athlete that we see in the world?

NO: I don’t really talk that much off the court. I feel like I tend to be a little bit reserved, but I think on the court I’m aggressive. I think that’s because I’m more sure of myself, because it’s something that I’m really good at.

TL: Winning takes discipline and sacrifice. What, if anything, do you feel like you’ve had to sacrifice or miss out on as you progressed in your tennis career?

NO: I wouldn’t really say I missed anything. I think if you’re thrown into the life that I’ve had, then you would think that you’ve sacrificed something. But growing up, I’ve done the same exact thing my whole life, so I didn’t really feel like I was missing anything. But I think maybe normal kids would miss their friends, because you have to practice for long hours and you don’t really get that many breaks other than, maybe, one day off during the weekend, and it’s usually Sunday.

TL: Do you feel like you’re able to have close friendships?

NO: I have like two. [Laughs.] We’ve been close ever since I was younger. And by younger, I mean like three years ago. Whenever I talk to them it’s a really good time, so I’m really glad that they’re my friends. I always apologize to them because I feel like they’re sacrificing something by being my friend.

TL: You’ve been playing tennis since childhood. Do you remember the moment you realized you were really good at tennis?

NO: Yeah. [Laughs.] I think I was 16 or 15, maybe 16. I played a WTA [event] and I beat a really good player. And that’s when I realized that maybe I can possibly do something with my career.

TL: Do you remember who you were playing?

NO: Yeah, I was playing Sam Stosur.

TL: When you step on the court, are you feeling an overwhelming love of the game, or largely a desire to win?

NO: I think it depends on the match. Usually, I’m just really happy to be on the court and like for people to be watching; especially on the bigger stadiums, I think there’s more of a grateful feeling. But then, when it gets closer, maybe the semis or the finals, then you just really want to win. So yeah, it sort of flip-flops.

TL: I’ve read reports that quote you saying you’re not interested in putting success over happiness. How do you define happiness?

NO: My idea of happiness is waking up and just being excited to do the things that I’m about to do, and just having a good feeling surrounded by all the people. Because tennis players’ career is not that long. It is if you stretch it as long as you want, but normally we don’t have like a 50-year career span, or anything like that. I want this part of my life to be the best. I’m No. 1 now, I won two Grand Slams and I just want to wake up every day happy and be excited to train. That’s what I describe happiness as.

TL: You’re multiracial — Japanese, Haitian, American. How do you think that informs the way you see the world, if it informs it at all?

NO: I just think that it gives me more perspective. Because I’m able to sort of relate to two different sides, and maybe most people can only relate to one side. I think I might see the world a little bit different from everyone else, because I grew up with two cultures. How do I say it? There’s two groups and I’m sort of merged in-between them.

TL: You were born in Japan, but you were raised in the U.S. Why did you decide to compete for Japan and not the United States?

NO: My mom’s Japanese, my father’s Haitian. I grew up in a Japanese and Haitian household. If anything, it would’ve been between three rather than two. I just chose Japanese because my mother was Japanese and I felt closer to that.

TL: If you could go back in time and give a piece of advice to your younger self, say, 13-year-old Naomi, what would you tell her?

NO: I would tell her to stop eating so much rice. But I would also say that dreams don’t have to just be dreams. You can make it a reality; if you just keep pushing and keep trying, then eventually you’ll reach your goal. And if that takes a few years, then that’s great, but if it takes 10 or 20, then that’s part of the process.

TL: Do you love rice? Is that one of your favorite things?

NO: Rice goes with everything.

Sylvia Hatchell, UNC women’s basketball coach, resigns after being accused of berating players and making racial remarks

She fostered a culture in which injured players reportedly felt pressured to rush back to competition

In a country where soccer is king, few women players can make a living

Women’s soccer has never been more popular in Spain. But players still must bargain for equality.

Hall of Fame golfer Marilynn Smith dies at 89

Smith helped found the LPGA, the world’s oldest women’s sports organization