I hear this a lot, usually about sexualised behaviour or stropiness!
I agree they get exposed to adult material earlier but they don't "grow up".
My father was working fulltime at 14yo and had an apprentice working for him by the time he was 16yo.
My grandfather was supporting his widowed mother and disabled sister by the time he was 15yo
My Grandmother worked in service from 14yo.
My 16 & 18 yo think staying in bed until lunchtime is perfectly reasonable (although they do have PT jobs) and have no idea what it is to feel insecurity or responsibility of any sort. That's my fault but I don't think it's unusual? It's probably a good thing really and I wouldn't want the life I describe about for me DC (or me) but they certainly haven't "grown up" earlier than previous generations.