I also was skinny until puberty, and then fairly "not fat" until young adulthood. I first gained weight in my early 20s - coincidentally, one of the most hellish periods of my life - and then took it off again in my later 20s. Now I'm working off the baby weight.
Being shapely, or thin, or fit, whatever you want to call it, it feels good. Quite good. You enjoy having your picture taken, among other things. For me, it's worth fighting to be shapely, it's worth giving up favorite foods for a while to get back there, and then really monitoring myself to stay there. It's a good feeling. You can practice for this good feeling by feeling good about your hard work and the progress you do make with your weight loss efforts.
