I think it depends more on the type of person rather than the age they've reached. Myself, I can't stand being the centre of attention. I fully realized this when my 21st came around, and my friends got completely wasted in celebration, even though I asked them specifically not to. Even though it was my birthday, I was the only one not enjoying myself that night. For my 22nd, I just went to a 7:00PM movie with a couple of close friends, and went to bed early - and actually ended up enjoying myself far more.
Contrast that with my one friend, who throws a party every year regardless of his age, and for that one day becomes the most selfish, self-centred person on the planet. He's been known to demand alcohol from people, or force everyone in the room to remove their pants, or other nonsense that would never fly if it weren't for the fact that it was his birthday.
So, in summary: screechy centre-of-attention types love them while introverted shut-ins hate them.