My girlfriends mother is against our relationship. What can I do to help?

I talked about this in the chat room earlier but would really like a little more input. My girlfriend is 18 and I'm 22 and we've been together for about 3 months now. I have no doubt in my mind that love each other greatly. We share a connection that is amazingly indescribable. She is from Indiana but she came down to Arizona to go to school at ASU, which I currently attend, and is currently back at home for Christmas break. When she returned home, she decided to tell her mother about her new boyfriend. Her mom seems to be strongly against us being together because I'm older and "more experienced" than her. I honestly believe that it has to do with the fact that her mom doesn't really know anything about me and that she is afraid of her daughter being with a stranger living 1000 miles away. She could also argue that a boyfriend would cause her to lose focus with her studies which isn't true because she's taking many of the classes I've already taken seeing as our majors are fairly similar. Not to mention we were both named to the Dean's List this past semester for superior academic performance. I'm not a complete stranger though considering I've met her mother and her father on two separate occasions when they came down to Arizona to visit. I was also invited out to dinner and then breakfast the very next morning by her grandparents while they were visiting. Of course, they didn't know we were dating at the time. My girlfriend is extremely upset with the situation and I want to do whatever I can to help. Her and her mom are super close and she feels that her mom will badger her until she gets what she wants. I'm not trying to come in between her and her family and I'm not trying to steal her away. I understand that her mom is worried about her but I truly love this girl and would do anything in my power to keep that smile on her face. She comes back in 15 days but I'm afraid that I'm losing her. What can I do to help?