Teenagers and this i dont care phase?

[Bob]

Alright so I'm a teen myself im 15 but recently I've noticed people are going at life the wrong way from my look of things like they do stupid stuff like drink, smoke have sex then while on social media they post dirty pictures of themselves either sexy pictures of them wearing no tops or tops but with some sort of sexy clothing thing like leggings for girls or just guys topless showing off abs then they say..

"I don't care" like is this a rebel stage against teens? are they going through the phase I'm not like this.. I'm actually mature going to school getting an education and like those type of girls don't even like me? I'm not the best looking for facial features but like whats up with teens now a days lol?