The grumpy old lady in the hallmark cards (the one who is perpetually wearing slippers and a bathrobe and says things like, "If each day is a gift, I'd like to know where to return Mondays") is named Maxine. Which wouldn't bother me, except that I knew an actual Maxine who could have been the prototype for the Hallmark character. I want to like the name, it has all of the benchmarks for revival, but I can't get past the grumpy/frumpy old lady-ness. And your daughter won't thank you for "Maxie" when she hits junior high.
My coworker's wife is named Maxine, and when I first heard her name, I cringed and thought some not-nice things about it. But after getting to know him and her (and hearing it over and over and over), I'm really loving this name, and I hope to see it a lot more. Can't say the same for the nn Maxie, which I agree with pp will not seem like a great idea when she goes through puberty (or when her peers do, more accurately).
I feel so-so about Maxine. I like Max as a nickname instead of Maxie. I feel like it's on par with Andy. Totally boy or girl, but that's really just how I feel I know some others would disagree.
I have to say I definitely prefer Charlotte, but I know that's really popular so if that's a concern for you Maxie may be the best bet.
Although you could always combine the two. Maxine Charlotte or Charlotte Maxine. GL!