Now 23, the former iCarly star admits maintaining a positive body image as a teenager was difficult, because she always felt like she was being judged by her peers.

"I definitely had moments when I didn't want to go to a pool party because I was like, 'Oh my gosh, I'll have to wear a bathing suit!'" she tells People. "Just the whole, like, thing of going somewhere and having your body be on display. It's scary. I was so shy."

But Miranda admits moving away from home and studying at the University of Southern California really helped build her confidence, adding, "It helped me come out of my shell."

"I'm at a place where I'm, like, really comfortable in my own skin," she adds. "I don't worry anywhere near as much as I used to. When I was younger, I would just stress about everything and I wanted everything to go well so badly that I didn't really enjoy the moment enough."

And if she could go back in time and offer her younger self a little sage advice, she'd say, "Just enjoy everything and relax."

The School of Rock star also tells the magazine she has the same laid back approach to her fitness regime: "I don't ever go to the gym," she reveals. "I just hike a lot. My best friend and I walk near my house every night."

But the young actress will go all out for a healthy feast, giggling, "I would drive 40 miles to get a good salad."