(USA)How old to buy a vibrator??

I’m 15 and I want to buy a new vibrator that my friend bought me as a joke and my mom doesn’t know that I have it and that I use it. The one I have is like the little egg kind but I want like a GOOD😏😏😏 one... the only problem is that I can’t order things offline without her knowing what I’m buying, and I can’t ask my friend because I don’t want to ask her because that’s kinda awkward. The only way is to go to a actual store😭