Really trying this time

Hi, I have struggled with my weight for almost 20 years, I have tried diets, working out, but never really put my heart into it. I was diagnosed with hypothyroidism (hashimoto's) about 10 years ago and have used that as an excuse to never really try to loose weight.
I am tired of getting winded walking up the stairs, of hearing my knees crack and pop as I walk across the floor. I have to do something. It's time. I'm hoping to stay motivated and always need inspiration so I have been looking at the message boards and blogs here. They seem to help me. This is going to be my year, I CAN do this.