Does he think of me as a little sister or more?

last summer this guy who i had known a bit for a while (our parents are friends) started texting me and and i was sure that it was just as friends, last summer we both went to the glastonbury and he texted me the whole time asking to meet up but i was with my friends parents most of the time (i was only fifteen) so in the end we met up for a bout fifteen minutes and just chatted and stuff. Then on the last night he phoned me saying he really wanted to see me but i had already gone home. The next day i left to go on Holiday for two weeks and by the time i had come back he had gone off to uni abroad. We chatted on facebook almost every night and he always asked me to skype him bt i didn't really want my parents finding out and eventually we stopped talking as much. He came back at christmas and it was quite awkward. He is back for summer now and texts me quite allot but sometimes when i see him its like we don't know what to say to each other and sometimes we have a laugh. He is 20 and i am 16 and usually i don't notice the age difference but sometimes it feels like he knows so much more than me and i can never tell what he is thinking as he sends such mixed messages.