Uh, grow up? I really don't see how this is a "grow up" situation. I really don't think it boils down to Erin being immature. I think a more appropriate response would have been "mind your own business," or maybe "take your damn meds," since we've just been told that she has medication to help with her condition but she's refusing to take it for some bizarre reason.
On the other hand, some of her behavior that led up to this situation could be seen as immature, I suppose. Sneaking into Clutch's house to swipe his Xbox just to spite him for preferring consoles to PCs is pretty childish. Then again so was his mocking Erin for her own preferences. So yeah...pot calling the kettle black there? Well granted her behavior was much more childish than his, but they were still along the same vein.
Ugh, this is getting complicated. Why do web comics which start out focusing on humor always seem to inevitably try to turn soap opera serious? All we need now is for one of the female characters to have a miscarriage.
Oh yes, I went there.