First of all happy birthday!
Also since this is your birthday, you could use this opportunity as a starting point that is hard to go back on. Think of today as the birth of the new healthier you. You are (metephorically) a newborn as far as health is concerned, and so its okay if you start out slow, and its okay if you mess up as long as you keep going. Think about it, newborns have to learn how to walk and its a long process. First they have to learn to hold their head up, then they move in turn to scooting, sitting up, crawling, pulling themselves up on coffee tables, and finally taking a few small shaky steps, and there are lot of spills and tumbles along the way. But they keep trying and by the time they are two they are running all over the place.
You can do the same thing with your health. It's SO hard at first, and everyone makes mistakes, but if you keep trying, think of where you'll be next year, or two years from now! You CAN do this!
Happy Birthday!