Okay, I think Penny is, indeed, taking the overheard conversation as Aggie talking about 'coming out' as Lisa's gal-pal. Which means that if she does launch a counter-strike, it's gonna blow up in her face, horribly. Let's face it--after all the times lately that Aggie has shown her up, a 'queer smear' campaign, if disproven, would be exactly the thing to finish Penny's current downward slide, if it didn't work. Another possibility is that Penny does interpret it reasonably accurately, and so decides to spy around--finding out that Aggie is a couple of "I do"s from becoming Karen's step-sister-in-law could be... well, fuel for some sort of attack, I'm sure.
Also, for purposes of this conversation, I think it's pretty clear that Aggie does not yet know who Charisma's kid is, or that Karen's coming, too. She'd be using a stronger word than 'awkward' when describing it to Lisa, if she did.
I also wonder who is in the other stall. Those aren't... stylish shoes, of the sort we'd expect to see on most of the girls in this school. I mean, I'm sure they're comfortable, but really, they're kinda... ugly
, wouldn't you say? Although if I'm right, then I'm sure that Char is just the person to keep an inaccurate accusation of lesbianism... from spinning out... Oh, I give up--I can't even TYPE it with a straight face.
So, yeah, lots of potential for disaster from this particular moment.