If you’re a millennial, it’s likely that “Matilda,” “Mrs. Doubtfire” and “Miracle on 34th Street” were in heavy rotation during your childhood. This also means Mara Wilson, the little girl with brown bangs and a slight lisp, still holds a special little piece of your heart.

Those memories are fond, but Wilson, now 29, has since distanced herself from her childhood career — penning a 2012 blog post that detailed her decision to quit acting — and instead now lends her name to bylines in the likes of   McSweeney’s, The New York Times and the Toast (RIP). Her quick wit, humor and thoughtfulness have earned her more than 300,000 followers on Twitter, where she continues answers the perpetual question: “What are you doing now?”

In fact, it’s the title of her new book, “Where Am I Now: True Stories of Girlhood and Accidental Fame,” out Sept. 13 from Penguin. The NYU grad’s intimate collection of essays describe her years on set, the pressures of a postpubescent Hollywood and the pangs of growing up that affect us all — child star, or not. Wilson chats about her decision to pen a memoir, the late Robin Williams and what it’s like to date when everyone’s still a “Matilda” fan.

How did the idea to write a book of essays all come together?

I always wanted to write a book. Even as a child, I told people I wanted to be an author when I grew up. I thought acting was my thing for a while, and I devoted all my time and energy to it, but I was always writing whenever I could — writing my blog, or doing essays. I had so many things I wanted to write about, but it was Cracked.com that asked me to do a list on child stars and I thought I could be more interested in doing something like that. 

In the book, you go into depth about when you were diagnosed with OCD when you were younger and the concern of what the press would say. Why was that important to include in the book?

It was important to me. I wish more celebrities would speak out on having it. I remember when I was diagnosed, looking up [online] and seeing who else had it too. You get one interview with Cameron Diaz saying she’s afraid of germs that was blown up to her having OCD. She later said she didn’t have a disorder. It’s misunderstood and mischaracterized, and I don’t think it’s usually explained very well. I think Maria Bramford talking about her OCD was great. More people need to do that. I have a platform, and I have a fan base. I’m not world famous, but I think it could help [other people] if I speak out, too.

Do you feel people expect child stars to fail or be troubled?

We’re an easy and acceptable target; being a child actor sets up this perfect storm. You have people telling them they’re great over and over again, and people doing things for them without their learning to do things themselves, and getting rewarded for how you look, which inevitably changes. It’s a perfect storm of things that can go wrong and damage a person.

There’s a funny bit in the book about being worried that your OKCupid profile will get put on blast on Gawker.

I’ve definitely had people — guys mostly — come up to me say, “I had a crush on you when I was a child,” and I’m like, “Well, OK, that feels uncomfortable to me.” I usually tend to stay away from that. My first serious boyfriend had never seen “Matilda” and I think at that time, it was good. Now it’s not as big of a deal to me, but I would never date a fan. That would be so unfair to them — to have to deal with me, instead of this idealized version of a muse figure.

There’s a part of the book that’s dedicated to your relationship with Robin Williams, both during “Mrs. Doubtfire,” and later in life. Was the decision to include him in his own separate way important to you?

I felt like it was something that had to be said. I wanted to pay tribute to him and I had some fun memories of him that didn’t really fit anywhere else in the book. It felt fitting to give him his own chapter because Robin was one of the first people I worked with who was so wonderful. Sally Field and the DeVitos were incredible, too, but it just felt appropriate.

You made   a guest spot on “Broad City,” which had some fans’ hopes up that you would start acting again — was that a one-off?

It’s a one-off. In the New York comedy world, everyone’s been on “Broad City.” I was at a party the other night and someone was like, “Oh I’m on ‘Broad City’ this week,” and I said, “Oh I’m on it next week,” and someone else said, “I was on it last week.” [Laughs] I love the show and the people who work on it are amazing — but when people ask about [my going back into] acting, I’m like, “Um, no. I was playing waitress number two.” 

If you go:

Sept 14 at 7 p.m.
The Astoria Bookshop
3129 31st St, Astoria
astoriabookshop.com

Sept. 17 at noon
Ample Hills Creamery
305 Nevins St., Brooklyn
amplehills.com

Sept. 15 at 6 p.m.
Sponsored by Harvard Bookstore
The Brattle Theater, “Matilda” screening to follow
40 Brattle St., Cambridge
Tickets start at $5, harvard.com