As thin as what?
Or do you mean "wasn't?"
I'm just saying, I have Gal's body type. I used to be that thin - tiny arms, thighs didn't touch, the whole bit. (To be fair, my skinniest was when I was recovering from stomach flu and couldn't eat much. My arms have always been skinny.)
My body CHANGED after I started lifting. My only rationale is that women's bodies are really weird, and for someone my size, even a little change makes a big difference.
I have a nice layer of fat on my stomach where there was nothing but hipbone and concavity there before. My legs are bigger for sure, and it's not all muscle either. I have hips now. I'm not sure how much is muscle or how much is fat, but hips are hips and my husband isn't complaining.
There will be certain things that won't be magically fixed with weightlifting. If you have small wrists you're stuck with them. My arms are still sticks, although they are a bit denser and my friends can tell my shoulders are a little bigger now. My back is also denser.
Most importantly, I feel that I walk differently. She will move differently after she's been working out. I think that will sell her more than just having muscles - how she moves. You do what you can with the mass and then let the movement do the rest of the selling.
But do you look like you could take on an army?