Self Esteem Issues!

Last night my brother offered to take me to Planet Fitness for the first time ever. I was like sure okay. So we got ready and when we pulled into the parking lot we drove by to see how crowded it was inside. As usual my self esteem issues got the best of me. I chickened myself out of going and I think my brother was angry, which is understandable. But he is built. He isn't bigger like me. We went home and I rode my elliptical for 30 minutes. After, I cried. I don't know if I cried because I was angry for not going in there or if I cried because I felt like giving up, or both. I put up this front to everyone around me like I don't care what people think of me, but obviously deep down I do. I guess I was scared that those thin, fit girls running on the treadmills would have looked at me like I was a cow or like I wasn't going to do good. I don't know. What I do know, is that I need to get over my fear of people judging me and go in there and exercise like a BOSS.