I know where you're coming from when you say it's a battle to prove yourself, but think that may be part of the problem. You're putting too much pressure on yourself to impress and that pressure is causing all the problems you experience. Try putting yourself in a social situation that includes girls, not with the intention of impressing them, but because it's something that interests. This could be some sort of club, or maybe a social with work colleagues. The more you talk to girls, hopefully the more comfortable you'll be and the less likely the foot will enter your mouth

Personally I suffer from a similar thing. I'm fine talking to the women at work (not that there's many of them ), but put me in a social situation and I'm rubbish. I'm crap at social, even when it's blokes. I feel I lack social skill and just retreat into a shell, listening to everyone else - kind of like the proverbial fly on the wall.