I'm 20/f and have often wondered this. I've only had one serious boyfriend in the past but our relationship never got that far (my birthmark covers my thigh and we never got "hot n heavy" enough for him to see). lol. I'll say to you what everyone else has said...if he really loves you then it wont be a problem. if he freaks out about it when you tell him or show him, then hes not the right person for you. there is someone out there for everyone, and that perfect someone will love you for you.