feeling old

Today was day 2 of my new working out at the gym plan. When I go to the gym, I feel old and dumb. I think part of the problem is that I'm being cheap (and intend to continue being cheap) by using the university gym, which is free of cost. The university gym is obviously intended for college students and I am no longer a college student, nor do I have the body I did when I was in college. The girls that are working out on the machines around me are wearing, for the most part, tight workout wear. I am in my post-childbirth baggy t-shirt and cotton shorts. I am making an effort to "fit in" a little better by wearing my sorority shirts, but I'm guessing that it makes me look even older since the dates on these shirts are anywhere from 1999-2003.
I did occasionally hit the gym at Gettysburg, but more often than not went running around campus. I'm not well versed in gym machinery, so I always feel as though others are looking at me because I'm using something incorrectly. Hopefully by taking advantage of the gym more often, my social anxiety in regards to the gym will work itself out. The whole idea behind this workout plan is to get myself into pre-pregnancy shape (I'm at pre-pregnancy weight but somehow I'm still a lot fatter).