I have to say the YMCA is the best place to go in my opinion. I went to 24/HR fitness because for awhile I had weird hours and it felt so.. fake? I mean it wasn't but the people there felt like barbies and I felt out of place. I signed up at the YMCA with my mother and we've been going on and off ( More lately ). The YMCA has everything 24/hr fitness had all the machines but the people there are -REAL- bigger girls like you and I and I can honestly say I got the best workout there because I just dont pay attention. Also if you like swimming the YMCA ( Not sure if they do where you're from.. ) has swim Aerobics . I weighed 260 at one point.. went for a summer and lost 20 pounds! I wasnt even really dieting and ontop of it I dropped almost 2 pant sizes. I got a great workout and It felt like nothing because I was in the nice cool water and you dont notice the sweat haha.
Most other people at the gym will thing everyone else is looking at them too. If they look, it doesn't matter at the end of the day. Even a snarky comment doesn't matter. You're doing this for yourself and no one else.
I walk "loops" in my yard. I figured out my distance with a pedometer, and do what I can.
If you don't have a pedometer, you can carry a handful of pennies in your pocket, and move one penny to the other pocket every time you complete once around. That'll help you know how you're improving.
I do this in the winter too, as long as I can keep my "loop" shoveled out.