Urgent help needed about potential crush

So for records I’m 23 he’s 19(found out from a friend) So there’s this guy that I always walk past and he keeps staring at me whenever we do. We keep making eye contact so much. At first I was like such a weirdo but then like a few months later I smiled at him idky it was unexpected and unplanned and I don’t know I kind of found him attractive and he immediately smiled back. Then didn’t see him for two months and then I saw him and I smiled and he smiled again. Then two days ago, this guy waves at me from a distance I thought it was for someone else at first but then went close and realised it was for me

So I waved and smiled and said hi and he said hi too. Then I mean I said hi twice and he didn’t say hi back he just smiled. And then yesterday this guy has a friend group right of like 18-19 year olds whatever and I smile and he just stares/ makes strong eye contact with no smile.

Is it because he’s with his friends? I was so ****ed that now I’m gonna take another route to avoid him

Does he like me by the way