Too big to go back to what? To big to go back to being more active and eating healthier? Nobody is too big for that.
Losing weight is a very achievable goal as long as we keep it realistic and take the steps towards making it come true. Choosing to watch our food intake... making sure that most of our foods are portioned properly and are filling our nutrition requirements... and then adding in activity. A walk, a bike ride, a game outdoors, gardening, dancing to music, taking the stairs, parking further from the stores.... it's all added activity. It's all extra steps.
Doing nothing means that nothing changes. And that's scarier!
You can do this.