You don't ask for another date, If there is chemistry there, some time during the first date there will be a moment where you are semi alone and a lul in the conversation, you take advantage of the moment and go for it, or puss out. I had many friends in high school and college that asked me how i was with so many girls, my reply was, "for the one chick you see me with, you don't see how many times i got shot down."
Confidence and siezing your opprotunities > letting a woman play with your head.
She's 22. if she likes you you can kiss her, if not, she will shoot you down. being rejected is better than wondering what some broad is thinking.