It's not something Madoka seems to have to think about long. Sure, she may not know everything about Romeo, but she think she has a pretty good idea of what the boy is like.. And he does seem like he'd like it. If not just since Romeo seems to appreciate just about everything in life.

"You should! If you don't find enough, just let me know.. I'll gladly share some with Romeo as well. He's a friend of mine too."

Yes, there's a 'too' there, because she's just assuming the other must be friends with her roommates. Who isn't friends with their roomates, right! Everyone is! Clearly!