I'm turning 28 in October. *gasp!* I need a coffin over here, stat!
I've been a fan of anime since I was 16, but loved animation in general for much longer than that. I remember being a teenager and being told I was too old to still be watching cartoons. I was living in Michigan at the time, the internet was in the process of becoming mainstream, and I was just very isolated. I had a few friends that shared interests, but on the whole, I had a hard time finding a support system to geek out with. Also, at the time, anime was impossible to find in Michigan. What you got is what you could find on TV, which was badly edited Sailor Moon. I found a store that sold bootleg video tapes straight from Japan. Horrible quality and there's only like two episodes per tape, and they never had all the tapes you needed to have any clue of what was happening.
So, skip forward 16 years, I love Kumoricon for what it provides to fans of all ages. We not only have this huge once a year event, but we have the mini event get togethers, the forums where people can chat openly, and fan held meet ups where you get 20 people in the area together to storm a movie theater on the opening night of the next big fandom movie. I'm envious of people who discover this outlet when they're a teenager, because it's not just a convention, it's the support system I never had growing up. I got involved because of friends, and I've made so many friends through the con, most of whom are around my own age, but there's a few teenagers I consider my friends as well. People are people, no matter what age they are.
So, when a teenager comes onto the forums and puts on a spaztasic OMG I NEVER KNEW THIS EXISTED!1! post, I just take a deep breath and remember back to when I was that age and know if I'd had this sort of a place to come to I probably would have been spazzy about it as well.
As far as meetups are concerned, I don't think I've ever been to a meet up that's me and a bunch of teenagers. And actually, most of the stuff I try to arrange it's people over 18 who show up, because teenagers don't have the freedom to just go where ever they want whenever they want. And even if you are in the minority as far as your age group is concerned, you just hang out, listen, and have fun.
If I meet someone who is older and has been a fan of anime longer than I've even known about it, I've got a huge amount of respect for that. Because for the people who've been around, it's not a fad. It's something they knew about way before it was mainstream, and they'll continue to watch anime long after the popular series of the year has been lost to obscurity.