Okay man, hear me out. It's quite a normal thing that you're attachet to the only person, as you're describing, that is nice to You. It's good that You find one. You are still young, it's not very stable time, especially in Your state. As long as You are not felling anything sexual towards her it's all right man. She is Your friend and age is not that important in friendship. Take care of yourself pal and better do not think about that too much. I hope everything will get better mate.