My entire family is very thin. My DH weighs only 145, my 16 year old only weighs 108 and my other kids are just as thin. My husband just assumed I got lazy. When I was married to my first husband he was always telling me I was working out wrong, when I would do something he would tell me that is not the way they do it in the army. I stopped working out in front of people. That way they don't bother me. Just start working out slowly and gradually add time to it. Once you start and see your progress it will become addictive. Keep a workout journal of your times and progress. Good luck!