Is it possible for a guy who's a lot older than you to like you?

I'm 13 and my friend's older bro is 17. I've been hanging out at my friend's house a lot and I don't see her brother a lot so I occasionally said hi to him and such when he was there. When we weren't talking we'd exchange glances and i know this because I always saw him looking at me out of the corner of my eye and i got curious and started glancing at him as well. He's also really nice to me and seems to try to be impressive whenever I walk into the room, like if he's playing guitar and talking with his sister and i walk in he'll start avoiding certain subjects and play really hard songs really well instead of just playing random ones. He also comes to hang out with me and my friend whenever we're at her house to say hi, well, whenever he's there at least, because i barely ever see him. He also doesn't mind me and my older brother who's his age says that I can be really annoying sometimes (however there's a history of sibling rivalry in my family, + but then again he's my brother haha). I think he might like me because everyone always confuses me for a 15 or 16 year old and someones even thought I was 18 once, and im really tall for my age as well. most of the time i act mature around people, or at least that's what everyone says, so many of my friends are older than I am. I feel a bit stupid asking this question because lots of young girls around my age seem to mistake nice guys for liking them and i dont want to be stupid like them and get embarred. however my friend has said that he's liked girls younger than him, some even 3 years younger and he recently broke up with his girlfriend who was a year younger than him. lately i've been also really caring about people and outgoing more than usual and i dont know whats up with that and when i get like this i seem to make lots of new friends.his ex-girlfriend (btw i met his ex-girlfriend before they dated) was really nice, outgoing and caring so i think i may have unintentionally reminded him of her personality. at first he seemed to be reluctant in talking to me when i first met him though and he always refuses to hug or do any other nice things to his sister when i'm around. whenever guys get like this around me i end up finding out that they like me but i dont know if this is just a coincidence or if seventh grade boys just happen to do that a lot around girls. im not going to be terribly sad if i find out he doesnt have feelings for me and i wont be overjoyed if i find out that he does care for me but im honestly just wondering. what does anyone else think???