In fifth grade, people started to dislike Pokemon, especially when I started shiny hunting, because they thought I was boring and ruined everything. lol. They also got action replays and stuff so it was no fun for me either. That didn't mean it was bad, though.
From sixth to eighth, everyone made fun of me for playing, even though these were specifically the three years I did NOT play often. I was never a big fan of Generation V, mainly due to the lack of old Pokemon. My friends who were still interested made fun of me, too, and when I helped them in the games, which was very common since I knew a lot more than them about the games that I didn't play, they'd just laugh in my face and not help me with anything.
I'm in ninth grade now, and even though the first month of school just ended, I can tell there will be less people nagging me about it. I've started to play more to prepare for X and Y, which I think will be a great generation. I see some older kids in a few of my classes that have their GBA's playing Pokemon RBY, and I also heard somewhere that there is a Pokemon Club in my school. My mom probably won't let me join, but it'd be fun if I could!
So yeah. I think it depends on the people you're with, but if you like it, don't let others stop you!