Please know that part of growing up is trying on "different hats." We all need to find out who we are. And sometimes, that means that we do things that we regret later on while we were acting as a part of one group or another.
It's normal.
Please let it go. Learn from it. Make meaning from it if you can. In each and every situation in our lives, we can grow. What have you learned from this situation? What meaning for your life have you aquired?
If you can do this, then you are a success. And you can be proud.
Peace!