Going to the gym

How do you get over the self consciousness of going to the gym? I'm not in the best shape, and I'm older (43),back in my late teens and early 20s when I was in super good shape in the military it wasn't a big deal, but now that I'm older and overweight I find going to the gym near impossible when other people are there, especially when it is younger people.

I know they could give 0 shits about me, but still I go late at night, but if there are any cars in the parking lot I just drive on by and go back home. Sometimes I go back an hour ot two later and sometimes I just say screw it.

How do you get over the self conscious feeling of working out around people? It's disheartening.