Really self conscious about ... ?

The way I see it the past is the past. In the words of a character from a Disney movie, "You can either learn from it, or run from it." People may react differently at first but once its out there there's nothing left to hide and you'll feel a HUGE weight lifted off your shoulder. And in time it wont even be an issue with your peers. That's who you were but don't let it define who you are now. Courage isn't the absence of fear but the ability to control it. SO have some courage, relax, and wear that short sleeve short. It may feel awkward at first but in the end you'll be glad you did!