Ha ha, I know what you mean. It can be really difficult to navigate romantic stuff after you've been out of it for so long and especially if you're lacking confidence if things ended badly in your last relationship. My advice is to take it slow and don't get too invested early on. And have fun
I get where you're coming from OP, as I was in a similar position. I nearly threw up in the taxi on my way to my first date. The first one is the worst, then you just get used to it! Wishing you lots of luck
Honestly, I think there's no way to tell just yet from what you've told us. Him being bad at messaging might be a sign he's not that interested but some people are just bad at messaging! There's no rush though. Keep it casual and friendly. If he is interested, an opportunity will come up while you're chatting. e.g. "Oh you're also interested in X? Did you know there's an exhibition on..." I will say though to be very careful if you work together and he's more senior. I'm not claiming either of you would do anything untoward, but if you make a move and he says no, or if you date for a little while and things end, you still have to deal with the awkwardness of having to work with him every day. Plenty of people have had successful relationships with people they've met at work but my personal rule is not to get involved with anyone I work with.