Also 45, also ti.

But I'm immature, and look, er, 39. Perhaps I can still get one of those new-fangled plastic bike frames?

Motto: Don't rue your age.

PS -- why do older riders go for ti?

Because they can afford it whereas a 22 year old can't?

Because they've learned to value quality?

Because they know that something that's, uh, er, juuuuust a little softer than the hardest material is still going to work?

Because they are saving their joints?