It's fine. It was just a weird question. [Or at least she is going to pretend that she wasn't perturbed by him questioning the species of those around her.]

I've been here for...well, in a couple of months, I'll have been here for...three years. [She sounds actually a little surprised, as she doesn't really think about it that much.] ...But most people don't stay for that long. It's...not really something you may have to worry about.