My bunnies stomach's gurgle while they drink sometimes. I wouldn't worry at all about it.
Also, yes, bunnies do grow very quickly, I would't worry at all about it. YOu could keep track of her weight and see how fast she grows just for the fun of it if you like-I've done that with mine when they're babies. And, because of how quickly they grow, you want to probably take lots of pictures while she's still small. I thought I'd take more pictures of Ripley while he was little but he grew sooo quickly I didn't get too many.