[Zim, being tiny and all, has to look waaaaay up. He's now wondering if she's taller than the Tallest because wow, she's certainly taller than any human he's seen.]

Oh, I'm not one of these filthy humans. This is merely a brilliant disguise. [And if she is somehow human he'll just erase her mind later. Whatever. Anyway.]

You're on Earth, so you can forget about whatever reason you have for landing here. The Irken Empire's already marked it for conquest.