Geez. This is incredibly frustrating...I like this girl, but her family..?

Her parents are way overprotective, to the point that her mom doesnt even like her talking to boys...Shes 18, for crying out loud! I really care about her, and when her parents arent around, we talk a lot, she looks/ smiles at me, we pick on each other, etc... but when they're around, she'll barely talk to me, say like one thing, smile, and leave... mostly this happens at church, and i cant really do much to make her stay/ talk... She seems afraid of parental judgement, right? The times they're not around are great, because i can tak/ hang out with her freely, and i really get to know her those times...thing is, those times are pretty rare, and few/ far between. I'm about to give up, even though i like her a LOT. I start at her college in January... should i wait it out til then, or move on, even though thats the last thing i want to do.. the fact that she cant really converse a lot with me at church really just eats me up.=/