Having a similar issue. I'm probably a good bit older than you and the ladies l am 'interested' in are certainly not going to Uni unless they are actually teaching there
but lve been so long out of the dating game l doubt l would have any inkling if someone was interested in me. Trial and error l guess and just a case of re-learning the ropes. I think the thing is just to go with your gut feel and if it is wrong don't beat yourself up.
To give you an example l was in a pub the other weekend, it was still quite early and l was standing at the bar with my mate when this lass knocked into me but just kept on walking. Realised l knew her - also that she was in a break up situation with her ex - then a couple of minutes later she walked past us again to go to the loo. On her way back she looked me in the eye, smiled and dallied until l sort of took the hint and engaged her in a brief conversation I.e. what was she doing, had she sold her house, where was she going to live. But instead of pressing the issue l kinda retreated from the situation because l still don't have the confidence to push matters because l still haven't picked up the body language signals being given out. Like l said, too long out of the game so l need to get my act together...fast.