Honestly dear, I'm always more embarrassed about skipping the gym that I am about going. Especially if you're paying for it!! At my old college I used the gym like crazy even though it was full of tiny college girls (which made me ride the elliptical even harder because I want to get there!). I agree with the above poster that the attitude is generally good towards you when you go, only the most worthless kind of people are going to judge you for improving your quality of life, most of them are probably cheering you on silently.
You DESERVE this membership and you DESERVE to GO! Stop cheating yourself and shorting yourself and allow yourself the treat of stretching your body and working the kinks out, getting your heart pumping and getting stronger. These are all amazing gifts to give yourself. The HARDEST part is getting off the couch and putting on your gym clothes. At least in my case, once I get there I'm excited to jump on the machines and get started with my favorite exercise (which you may not have yet but which you will have by the end of your first week). See if you gym has a stretch machine and USE that sucker. That's my favorite part of the workout, stretching my tired muscles out after an invigorating exercise. I always feel so peaceful and comfortable in my own skin when I leave the gym, even if i'm sweaty and panting. It is so much FUN to get in shape, and your body is just begging for it, it will start to snap right back into shape after a couple of consistent workouts and it will just better more fun and easier.
There is nothing to be embarassed about, you should be the opposite of embarrassed because you're self-aware, and you're showing anyone that might think they're better than you that you can go to the gym and do whatever they can do, and that you're not allowing a little extra weight to dictate your life, your happiness and your well-being.
Tough love over. Do it sweetie, it's going to be so great and it's going to open the door for all the wonderful things you want to do in your life. You are just going to LOVE working out.