I Think It's A Sign

After watching the following video, I think I have a lot of soul searching and life reevaluating to do. This girl's name is Cari. My name is Keri. She said she had been overweight all her life. So have I. She 34 but I'm only 23. She's been in 2 of her friends' weddings. I've got to be in a wedding in October. The dress is strapless.
The last time I went to the doctor and saw what the scale read, I was mortified but still didn't do anything about it. I whole heartedly believe that if I don't do anything now that the way Cari was at 34 will be me. I began diets and what not before but can't seem to stick to them.
Just this weekend, Derek and I went to a state park and roamed around a little. The next day, my calf muscles were hurting. That's sad when you can't even walk up a small incline without losing your breath and having muscles ache the next day. This is it. Starting today.
Any encouragement or tips or what have you that you think would help, would be greatly appreciated.
Peace out! Much love!