Well if you like her man then just learn how to deal with your differences. You both are of age but she can't even go in the bar yet.
You both are in 2 different stages of you life: 1. You are ready to settle(I am thinking) 2. And she hasn't even experience the 21 & 22 party life & may not be ready ye.
Caring for each other is an easy thing if you both have the same feeling but what may make it hard is you both just being so different. The best way to handle thing is just except her for who she is so you both can adapt to each other.