It's possible. When I'm manic I'm mean! Other than that I am a nice person. I would seek medical advice. I was about that age when I noticed something was wrong but I didn't know what it was or who to talk to about it. It was a scary, lonely time. I'm sure if I had gone to the doctor about it the rest of my teens/early twenties would have gone a lot smoother. Even if it's not bipolar disorder, early detection is helpful with any mental health issue.