As soon as I finish the app, I will! (Just need to make the contact posts and finish writing her canon history!)
He's a year or two older (I don't think it's ever specified, but I may be wrong on that!) All of them have seen things, been forced to do things to survive, had to grow up very fast or they'd be dead. Gives them a harsh wisdom beyond their years. So not only could she legally drink everywhere, she's also very mature in most ways!
There will be an element of sass because she's not a pushover and not meek! But she'll do it respectfully and because I think she gets it and gets him. Yes, he's got his sadistic side, but his rules also keep them alive and even thriving as a group. And hey, at least he's not some weird death worshipping cultist like some people she's met!