Britney: What Was I Thinking?

In new promos for her upcoming documentary For the Record, airing on MTV on Nov. 30, Britney Spears is already opening up quite a bit on her troubled life.

"There's a lot that people don't now about me that I want them to know," she reveals in one, adding, "I don't think that anyone can prepare themselves for what stardom really brings."

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And for Britney, stardom brought a quick marriage, two children, a string of bizarre incidents and a hospitalization in only a few years, something she says has changed her for the better.

"I've been through a lot the past two or three years, and I've definitely grown up, big time," she muses. "I sit there and I look back and I'm like, 'I'm a smart person, like, what the hell was I thinking?"

The comeback queen also admits that tying the knot with Kevin Federline might not have been the best move, saying, "I think i married for the wrong reasons. Instead of following my heart and like doing something that made me really happy, I just did it for like, the idea of everything."

Check out the promos below!