I would love to ask her some specific questions about how she achieved this kind of success at such a young age but she does answer a couple of questions on her blog.
“How did you juggle college and writing?”
“The best answer I can give to this is: I prioritized writing. That sometimes sounds misleading, so I'll say this-- I did work hard, attend class, and maintain good grades. But: I also figured out exactly what was necessary to be in good standing in any given class and did only that .....But it's important, whether you're a writer or not, to remember that while you are a student, you are also a person. And I think you should prioritize being a person-- being healthy, sleeping, resting, hanging out with friends, exploring the world-- even at the expense of your grades. For me, part of being a person was writing. And I found that if I allowed myself time to be a person, when I did sit down to be a student, I worked HARD. I was far more focused during the time I set aside to work than I would have been if I had tried to work all day. So it's also a matter of using your time well. And you'll be able to use your time well if you have your priorities in order. That's my theory."
Obviously this applies to school or to a job. She emphasizes something we all already know but seeing someone so young put it into action is encouraging, and that is to prioritize, set time aside, and not let anything distract you from your ultimate goal.
“Is it hard being a "baby" in the published world? Does being so young hurt your chances or help?”
“Just to set the record straight: I was 21 when I wrote Divergent. BUT other talented authors like the delightful Kody Keplinger were even younger than that when they wrote their books. So this age question is an interesting one.
Being young didn't hurt my chances because it wasn't a factor. I didn't mention my age in query letters to agents; sometimes I didn't even mention that I was a student. JSV knew my age only because she'd met me in person, and she didn't care. She just wanted to see a good manuscript, and in that, she's not alone. I haven't met many people who care how young you are, as long as you write a good book.
In a certain sense it's difficult, because I'm just not as wise or mature as I'd like to be. That's not to say that I'm unwise and immature, because I'm not-- but sometimes I seriously struggle to handle the things that are on my plate, sometimes I react to things like a young person does (with stubbornness!), sometimes I get anxious about what's ahead of me because it feels too adult, too soon. Maybe older writers also have this struggle, but some of it is specific to my youth and my personality. I also know that I can only push my writing so far before I just have to say, "Wait. With time, wisdom. With wisdom, better writing."
But as far as my reception among other writers, or people in the publishing industry...being young is not a hindrance. Some people will make a thing out of it, but only in a good way ("And she's so young, too!"), in which case I try to remind myself I still have a lot to learn, so that it doesn't go to my head.”
From her Amazon Q&A, she answers a question about how being young informed her writing and the themes she addressed in Divergent:"Q: You’re a young author--is it your current adult perspective or not-so-recent teenage perspective that brought about the factions in the development of this story? Do you think that teens or adults are more likely to fit into categories in our current society?
Roth: Other aspects of my identity have more to do with the factions than my age. The faction system reflects my beliefs about human nature—that we can make even something as well-intentioned as virtue into an idol, or an evil thing. And that virtue as an end unto itself is worthless to us. I did spend a large portion of my adolescence trying to be as “good” as possible so that I could prove my worth to the people around me, to myself, to God, to everyone. It’s only now that I’m a little older that I realize I am unable to be truly “good” and that it’s my reasons for striving after virtue that need adjustment more than my behavior. In a sense, Divergent is me writing through that realization—everyone in Beatrice’s society believes that virtue is the end, the answer. I think that’s a little twisted.
I think we all secretly love and hate categories—love to get a firm hold on our identities, but hate to be confined—and I never loved and hated them more than when I was a teenager. That said: Though we hear a lot about high school cliques, I believe that adults categorize each other just as often, just in subtler ways. It is a dangerous tendency of ours. And it begins in adolescence."
I thought that last statement was rather profound.
She states that being young hasn't been an issue for her in the publishing industry but what's interesting is she didn't let it become an issue for herself. (I wouldn't worry as much now, but at 21 I'm not sure I would have had that kind of confidence and drive in college!) She knew what she wanted, she was disciplined in how she achieved her goal, and she did it without hesitation. It's encouraging to read about someone so young going after their dreams and making them come true in a big way.
P.S. If you are a writer/aspiring author, she gives lots of answers and advice on how she did it on her FAQ page here.