Yeah definitly bullyng in a young age can ruin you sense of self, you assume you are whortless because that is what the world tell you all the time and that insecurity become a part of your character, for me the worst part was i dint even notice this until i was already a man when you are young you dont have the maturity to notice this things you just assume that is the way things are
Bullys are self confident and as a consequence are more sociable so other students, parents, teacher and people in general and girls specially feel more sympathy for them and even when most adults denied this they feel rejection to kids who are been bullyed, because as a consequence of the abuse you become more introvert is dificult socialize when you are not self confident is dificult be a happy, cool and relax person if you are constantly verbally abuse, you assume everything that comes from you your words and ideas are less and you start to just hide your toughts, you dont have the chance to develop the social skills that are so important to have a happy normal life as an adult
Normies dont understand this kind of thing they believe you are introvert because you choose to (wich just show how stupid and shallow most normal people are) they think you have an internal switch wich you can turn on and automatically rewire your brain to behave in a way that is alien to your character an become the life of the party just like that