If you ever catch your crush accidentally liking one of your pictures from 2013, she likes you. There is no way around it.
If you ever catch your crush looking at you and then looking away when you make eye contact, she likes you.
If you ever notice that you see your crush a lot more than usual, she likes you.
If they get dilated and her pupils get really big, she likes you. Your pupils tend to grow when you see something you like.
Go up to her and start a conversation; flirt around with her. If you notice that she is flirting back, she likes you.
If she has her body open and vulnerable to you, she is facing you, and she is a little shy or nervous. Also, if she is playing with her hair, she likes you!