Sheesh, this girl sounds like she's got some issues of her own that she's projecting onto you!

I think you hit the nail on the head with your original post. I would say to her "Yes, you were skinny, but we got here the same way, and we're both going to have to work hard to make healthy changes and lose the weight. let's focus on the present and the future!"

Kill 'er with kindness. Hehe.