Is it normal that i eat a lot and dont gain weight?

I think I have a bigger stomach than most other humans, and that's not really a joke. Ive drunk a 2 liter of soda in a day multiple times, the usual meals at restaurants dont fill me up, unless its a huge steak or something, I can easily down a whole large pizza for dinner, and then some. But I don't gain any weight, no matter how much I over eat (im assuming its over eating unless my body is just built for mass quantities of food) I never gain any weight, I'm not skinny by any means, but im not exactly fat either, and I seem to have a respectable amount of muscle even if I haven't worked out a single day in my life (im a girl btw) Some people are like "wow youre so lucky" but it weirds me out, it doesnt make any sense, is it normal?