That is true, its not like you walk into a group of college girls and they strip right then and go after your dick, but personally I've found a somewhat successful tactic. First thing to realize is that women are frightened of men by nature, so you have to put them at ease, and lots of comments about how they are different from other girls their own age seems to work as well, making them feel like they are qualified despite their age.

A personal anecdote about pulling a 20 year old, and finding out that she was worried I just though of her as a stupid kid, then making a small effort to hint to her in conversation how impressed I was by her maturity seemed to go an awful long way .

There are a lot wiser people than me in this sub, so I can only speak for what worked for me, and I suppose it could be flukes but I'll take what I can get. Remember that validation is one of the most important things in the world to a woman because they are never sure of themselves and they need other people to reinforce their sense of self worth. Walking a fine line between providing that validation, while at the same time hinting subtly that they still might not be quite up to snuff seems to work for me.

I'd like to add that talking yourself up seems to overwhelm them and reinforce their inner belief that they aren't good enough, so you have to be careful with that. I suggest slight negs here and there, followed by some compliments related to their maturity. This seems to lead them towards wanting to prove themselves while at the same time feeling like you understand them.

You are right about social barriers, and this part is a bit trickier, I like to play on their innate hatred for social constraints, convincing them that attraction knows no barriers and that we could miss out on something that could be magical. And remember, the thought of being judged is like sunlight to a vampire, so you either have to convince her that those that would judge are simply jealous and frightened of taking a chance on living their life, or you have to make sure you have a place to take her where you can be alone and she doesn't have to worry about being judged.