my body image wasnt great as a teenager, from about 13 to 16 i couldnt leave the house unless i had make up on and wouldnt wear anything that wasnt a bit baggy. I've gotten much happier and more confident since then and i've been reasonably into a healthy weight range (prior to that i was always either just underweight or on the line) and stopped wearing make up 3 years ago.
It does get better once you're no longer a teenager i think.