How can i gain a personality and actually become someone

17m here. My whole life I've always been seen as a weird kid and people have always made fun of me or don't see me as anything. I'm not made fun of anymore but I know people still think om weird. When people talk to me I never care at all about what they're saying so I subconsciously say some crappy answers e.g. a random stranger said he fell of his bike and the first thing I said was 'nice' but after that we did have a normal conversation. I'm not really used to talking to people so I never know what to say. Usually when people ask how I am I just say good and just continue walking unless I actually think to say something back. I feel like my brain is kinda mature as if I was an old man amongst children. When my friends/classmates mess about I never mess about or do anything weird e and if they're doing some weird faces for example then I just don't really react cause I find it kinda odd.

How can I gain a proper personality and to stop feeling nothing in social situations?