I think I can relate to that kind of struggle mentioned in the opening post. There are times when people think you are only nervous around girls because you simply haven't been around enough of them, or you are too inexperienced, etc. And another thing common is they think you are immature and as you said, "treat you like a kid."
The truth is, you and I have probably been around enough girls, but have always avoided contact with them because we are so unsure of ourselves. And it's not just girls often, but anyone new or for some reason intimidating. It's not immaturity, and it's not "being around enough girls." Don't you think that's not the problem? The problem is having a program in the brain that automatically tells you to be afraid for some reason (probably stemming from child experience [programming]).
Of course, social phobia is probbaly the most misunderstood and under-recognized mental issue in the world. It is so mysterious to those who can't relate, and those who have it don't usually dare tell anyone, for obvious reasons, I think.
I wish I was able to flip a switch and change everything, but since I can't I will simply join the rest of you (hopefully) and try as hard as I can to RE-train my way of thinking. Habitually change our thought flow. I think it can largely be done.