I can never get "skinny"

I've always been thicker, and I'm TTC, but starting a diet now scares me because I have a history of letting my diets get out of control trying to get the perfect feminine body type. My legs and calves have always been thicker, not like other girls who have nice legs that are one size thighs and small calves and ankles. My legs are one size thighs, smaller calves but they're still really thick, and almost no difference in my ankles from my calves. Even when I worked out too a lot, my legs stayed the same and I only lost belly weight. Any tips?