there is a huge difference between someone in highschool and college.
"I'm in Highschool."
"I'm in College."
Those two sentences contrast with each other...A LOT, say it out loud. College is way more mature than Highschool...its a fact.
gaming girls at the age of early and late 20's (I'll refer to them as "college girls) isn't different from gaming girls in highschool. It's the same concept. You can still tease them and make them laugh and even kino them.
Now if you want to actually have college girls as girlfriends, I would think it is impossible, unless your social value is up the wazoo. It would be really hard for them to accept the fact that they are going out with a highschool student.
I have two sisters (one is 23 and the other is 26 and i game with their friends all the time, do they bite? no. I went to one of my sister's friend's son's birthday party (free food) and there were nothing but hot college girls. I was the AMOG of the group having all the girls laughing and getting tons of IoI's. I asked for numbers but they thought i was joking and laughed.
Gaming girls of older age is a definite yes. Not at the age of 17 though.