What is a good relationship built on?

Im really scared right now. Just the past 3 weeks with my gf she hasn't had too much time to talk on the phone and we go to different schools. usually i get like 2 mins every day and its just a goodnight. And im happy for that, it's just that it wasnt like this before. now the first 2 weeks were really hectic for her, but this week seems so easy, so im not quite sure what to think. I really want to ask her, but i feel like if I say it in like a condescending way, she'll take it the wrong way. I have been understanding about her work for the entire time, i just feel like 10 minutes a night is not much to ask.