The right size is the size you can reach and maintain by eating a healthy diet and getting regular exercise. Yes, there's a lot of hysteria about being a size 00.
When someone loves you or finds you attractive, it will be for your genuine physical and emotional assets. Bettering what you have through working out, education, a good diet, embracing love, is great.
Trying to be something you're not will only make you unhappy. I have wide hips. It does not matter if I'm a 00 or a 16. I can't change that. When you accept yourself "as is," you'll find people in your life who recognize that as a form of beauty. I used to feel terrible about being so "wide" across my lower body. When I started accepting it as it is, working out, eating well, I got all these compliments about my legs, butt, and hips. "Wait, no one can like those! They have cellulite and aren't in proportion with the top half of me!" Sorry, no dice. You accept yourself and people will like you. It's the breaks of the game.