My gf's parents want her to break up with me?

me and my gf have been dating for 6 months. i love this girl so much she makes me so happy and i couldn't imagine not having her in my life. we're both 16. she lives in georgia and i live in pennsylvania. she moved 2 months ago and we decided to continue our relationship. we both trust eachother and things have been great, but her parents want her to move on. they think its better for her to move on and go for another guy. i don't understand. they LOVED me when they were living here. it saddens me that her parents think i will cheat on their daughter. it really makes me sad knowing they want her to move on and find someone else. what should i do