talk me off the ledge?

I've been planning to keep Jessi in her crib until Jr. High, but over the last few days I've been having these crazy thoughts of moving her into a big girl bed. Her crib is super high, so I doubt she'll ever be able to climb out. So we can't really count on her telling us when she's ready, it's up to us to decide. She's just getting so big and I'm obsessed with showering her with things she doesn't need :) I was thinking it would be so fun to surprise her for her birthday with her new big girl bed! The only thing that really concerns me is the fact that she's upstairs by herself. We have a gate at the top of the stairs, but is is bad to put a childproof door handle on the inside of her door so she can't get out at night?

I mean...come on. How cute is this?? Since her room is already a "rockstar" theme, I doubt I'll change it until the girls move into a room together and something like this would be so stinking cute!

Source: Target

When did you move your little one? Should I hold off and wait until she's at least in 5th grade?