In a modern diverse society, such a question is laughable. Of course it's acceptable. I like crops tops too. And look, she's a smart teenager who is wearing her coat with it and will no doubt zip it up when cold enough.
Only a very close-minded hardass medieval-minded parent would NEVER let their daughter explore a more diverse fashion sense sometimes -especially for a casual occasion. Only a very closeminded person would just say its too immodest and ban it. You are allowed your opinion on it, of course. And you are allowed to impart whatever fashion wisdom you have to your kids. But forcing them to maintain outdated conservative principles ALL the fucking time seems kinda unreasonable to me, unless you actually live somewhere or are going to a location in which her wearing a croptop is against some rule (school, certain countries). In which case, you should teach your child that part of responsibility means planning your oitfit ahead of time to match the location/culture you are going too. But only a very closeminded person would not allow their child to safely explore what amounts to a very harmless and very popular fashion trend with the support and advice of family (rather then the risk of the kid doing it when you aren't around and they hide it) , simply because you don't like it. Do you ban everything you don't like? Do you let your kids do anything, explore anything and learn from them, or let them learn about themselves? As a parent you might have to accept that kids are kids and shouldn't be expected to be a perfect doll, who will grow up to believe and act and dress or whatever you want them to because you were strict enough. Will kids be influence by you are your ideals, sure. But it's also not wrong for anyone to be influenced by their personality or by fashion trends, or what their generation sees as acceptable. That is simply part of growing up and getting with the times...
