Don't worry, you'll eventually grow out of this attitude. Your confidence will increase. You won't have to say stuff like this in an effort to feel better about yourself. Hang in there and good luck.
I don't think it's that different from 30s. In some ways, anything post-college is similar in that your life doesn't revolve around an institution full of single peers.
There's a little bit of magic-numberism that goes on, I suppose: people have ideas about what age means and they'll use it for a proxy (you'll worry about much younger people being annoying or stupid, they'll suspect you'll be staid or weird). But for the most part, everybody who's looking is still basically looking for the right connection.
The only practical effects I've seen are around two clocks:
* the family clock: some people are more anxious to have kids before they get too much older, some people have decided the window is done (which changes who they can pair up with).
* the midlife crisis clock: people start trying harder to see if they can make their life exactly what they want, or insert something they wished they had when they were younger.
These might be the same clock, though. And they have been known to strike well before the 40s. :) YMMV.
I don't know. I got married during my 30s, so I have no need for dating. But at the same time, I'm way more confident and I'm sure I wouldn't suck as badly at it as I did during my 20s.