I feel like I act older than everyone I know

Since I was young I have always felt very detached from everyone. I was a good kid, and am now very successful in my early 20's. I am VERY grateful for everything in my life. My only concern is I feel very detached from everyone I know including my family. I feel like I can never relate to anyone and no one can relate to me. I have never had anything more than acquaintances even when I was younger. The older I get the more I feel like I will never have healthy, open, real relationships with anyone. Does anyone else feel this way? How do you cope?