My wife and I are both attending, I'm 31, she's 24. We've both been attending the local conventions (Sakuracon, Kumoricon, Akicon) for years now. We went through a period of time where we felt a little out of place as the crowds skewed a lot younger, and considered that maybe it was time for us to move on... but then we got back into cosplay, and the convention was a completely different experience for us again.
Now we just need to get better about being social with people we don't know at the convention. But you know how it goes, one step at a time. XD