I'm probably going to get crucified for this but...here's the thing, and I'm not saying this is right or wrong or whatever, but she's a young girl who doesn't have a 'normal life', she's a talented, in demand actress with the likes of Scorsese and Burton lining up for her. As someone said, she's home schooled and she has been working for quite a few years now. She's around adults a lot, much more than anyone her own age so it's not surprising that she's mature for her age. It happens with every child actor I've ever met, that includes both Fannings and Hailee Steinfeld by the way, lets not think for a second they're all sweet and innocent and not career focussed because trust me, they really are. The Fanning family are a machine.
I don't know about you but I certainly wasn't some little, cute innocent girl at 14 either and if someone had thrown designer dresses at me I'd have jumped at it too. Don't tell me you weren't in a hurry to grow up at that age. I agree, her outfits have been too mature for her but it seems to have been dialled back a little recently with the Miu Miu and the Chanel. That Burberry is awful though. Most of these events she goes to don't allow minors to stay after 11pm, so it's not like she's partying until 2am.
I've spent quite a bit of time with her and yes, she's a confident young woman (very bright), yes she's mature for her age and good grief is she media trained up to the eyeballs but I've never seen the precocious brat that everyone like to assume she is. Is she likeable? Well I suppose if mature teenagers with careers, ambition and strong conversational ability aren't your thing then no, she's probably not. We all have our opinions.