How do I know if this is really love? Does he like me back? HELP!!!?

So there is this guy at my school and I really..kind of like him? I don't really know what my "feelings" are for him but I know for a fact there is something going on...he almost gives me butterflies. I don't know if what I'm feeling is love or something else! We started talking at the beginning of the school year (August) because he is in most of my classes and he sits near/ or by me in those classes. I think I like him..but I'm don't know if I do or not. How do I know if he likes me? I want to know if he likes me... but I don't really know what guys do when they like a girl or what they talk like or anything like that. One day when I was in the hallway I was walking behind him and he passed one of his friends and the friend said "Ask her!!" and then the guy I like said "No..." and kind of smiled and walked away. I don't know what that means...boys are confusing and it's really annoying. But, I don't know if he likes me because he is always talking to this one girl who is older than him and I and they smile and laugh...It doesn't feel good seeing that. There was one day when he almost caught me looking at him in Algebra...it made me blush a bright pink and that pink stayed on my cheeks the whole day...It's crazy that a person can make you feel so happy inside. But I am confused and I don't know what to do about this guy!! This is really hard for me. Can anyone help? And please make your answer thoughtful...I really need some advice on this.

(Also I'm sorry this is long)