I know I've lost out on girls that were very interested in me and I was interested in them, but it felt impossible for me to make any kind of move. You may have to be the pursuer on this one. Especially if you like him! I am totally projecting here, but if he's approaching his mid 20s and hasn't had a girlfriend he may have a lot of built up anxiety trying to break the ice so to speak. It sounds like he's warming up to you so that's a good sign. Good luck :)