Getting my shit together

So I’ve decided I’m not happy with my body the way it is so I’m going to do something about it. I really struggle with eating healthy and have a huge sweet tooth, so any tips or ways to tackle this would be great, but also any exercise that can generally be done from home without having to spend a fortune on equipment ( too skint for the gym) I want to lose a bit of weight, but mostly just tone up and get in shape, possibly try to lower my boob size - 36G, I’m 17 and looking for a breast reduction next year but until I can show that it won’t change without weight loss it won’t happen so any advice would be great xx