Quantifier + comparative - so much drunk or so much drunker

I'd like to know what´s wrong in the sentence:

I didn't drink any more than the guys did, but I got so much drunker.

I believe it's the quantifier + the comparative that is wrong, but I'm not sure why. And one more thing: it's a teenage girl talking about hanging out with friends: when she says "guys", is she referring just to the boys in the group, or to the group in general (boys and girls)? Thank you!