I think I love this guy

I really like my friend’s older brother. Because he’s really sweet and kind, and he likes to make me laugh a lot as well. It would probably just be a simple crush if at times I didn’t feel him showing me that he’s interested. Like he has a girlfriend but I don’t know it’s very weird. Like one day he’ll make me laugh and he’ll be smiling at me, the next day he’ll totally ignore me and then the next day he’ll just be all quiet but stare at me. I don’t understand why he does that and it more or less confuses me. The other thing is he has a girlfriend, and theres also our age difference. Were 3 1/2 years apart, he just turned 18 and I will be 15 in october.

I don’t really understand why but I just really like him, and it’s hard for me to get him out of my head, I can tell it’s annoying my friends so I’m usually quiet about it now but I kind of need some advice on what to do. Cause basically I don’t know if he sees anything in me or what…and I’m unsure of what to do next and if I should do anything or not. His actions are just so confusing.