Just hang out with people you like, who cares if it's not people in the same grade... Well i suppose when those people leave the school you'll be alone again...
@havelmom
The manga has pretty much ended with the marriage proposal, there's no more actual plot left. AFAIK, the original webcomic just showed them graduating soon after that, and, after a timeskip, showed that they had a kid that goes to the same school. The end.
What we are seeing right now is the adaptation of 10 gorillion of webcomic's side stories that were written after the ending. It's not going to end any time soon.
Ah I know how that feels. Sawada's case is more like she doesn't know how to start conversation by her peers- thus she goes to those she's comfortable with. I'm sure someone on her year is as strange as her...good luck Sawada!
She could just go to the girls and say: Yeah, I got some people I know from out of school in the third year and you guys never talk to me, anyway here some chocolate what's your name?
Great way to get to know someone.