Look elsewhere..There are a lot of nice girls out there.Why pick one that will probably give you nothing but grief.Life has enough problems for you to solve. Look for a girl who has a great personality. One who is easy to talk to and is fun to be with. Pretty is not the answer. If you find one pretty who has the qualities mentioned, fine. If you don't care about trying to change the girls you described, that will be up to you, but why work so hard.?
Drop them both and explore for someone new! Someone who has all the things you like in a girl. Because it sounds like difficult girls give you a hard time and you don't like immature girls to be, well, immature.
Neither seem fun to be with, but if I were you and I had to choose then I would pick the second one, the immature one. The difficult girl is probably full of drama, and seems snobby from your point of view.
Could you see yourself marrying either one? If not why waste your time and heart? If she''s difficult now she won't get any easier. There are lots of great girls out there. Guard your heart. Or you'll carry un-necessary baggage into a relationship with the right girl... That could mess things up later. Take time getting to know a girl before jumping into a relationship.