What does his behavior mean?

I've developed a crush on this guy that works at this bank I go to. I've seen him a total of 5 times. The first 3 times he has helped me and the last 2 visits someone else was helping me when I seen him.

On my 3rd visit as I was leaving I looked back at him and I think he seen me. On my 4th visit it seemed like his behavior changed. Even though he wasn't the one helping me with my transaction I noticed he was going out of his way to look at me and trying to steal subtle glances of me. Also the first 3 times I seen him and he helped me he just seemed polite and professional.

On the 5th visit when I seen him he wasn't the one helping me again but I seen him look behind him pretending to look at something but trying to look at me.

Could his behavior mean he's interested in me or we have a connection? Or mutual attraction?

Also I'm pretty sure he's younger than me and he knows I'm older than him as he has seen my I. D.

What does his behavior mean?
Post Opinion