How to tell if a coworker likes me

So I’ve always been pretty cool with one of my coworkers. We talk about a lot of stuff. I was one of the firsts that he talked to about his breakup with his ex. He also told me about how thinks with his ex have been on and off. Somehow a rumor got spread about us being together and we joked about it. Recently we’ve talked about life as single people. We both talked to people and told each other about it. Then he stopped telling me about his potential girls and would diss his ex.

A week ago, we worked together. I tried talking about my guys on tinder and he seemed uninterested. He was telling me how he’s completely done with his ex now and telling me how he wants to start something new. He also kept playing footsie and just other stupid things. Then he asked about why I haven’t dated anyone younger and said “I’m not that young”. He kept making comments and I brushed them off but then thought about all this later. We was talking about my tattoos and he said he likes girls with tattoos.

Idk if it’s just in my mind. I also realized I’ve been flirty without realizing