Is this flirting? Does he like me too? Advice for liking an older guy?

I have been working with this guy who is 11 years older than me (I am 18, he is 29) for about 7 months or so. For probably the last 2 months, I have been having feelings for him.

He is so sweet and nice, and we get along together perfectly.

The other day before he left for the day he was playing with the stapler at work and this is our convo lol. Most of our conversations are like this and sometimes they last a long time while texting or talking face to face. Is this flirting?

Me: So just to tell you, you broke the stabler. So now I can't staple things!

Him: No I didn't

Me: umm yeh ya did

Him: Can't prove it

Me: Umm yeh I can. I saw you playing with it and now when I went to staple something (not my hand), it didn't work

Him: that will never stand in court

Me: umm its my word againist yours. I think so

Him: Nah I am way more popular nobody will belive me

Me: umm we never proved that so I don't think you are. everyone loves me

Him: hmmm don't think that but I'll let you think that for now

Me: you know I am right so don't deny it lol

End of convo

we have an ongoing joke that he is supposeldy more popular than I am at work lol

We always flirt like this and I am not sure what to do? I have feelings for him!