My parents were 39 an 34 when they adopted me, and I thought they were so
old at the time.
My views have changed dramatically with time, especially with more and more parents being in their mid to late 30's when their first (or only) children are born. My DF will be in his 40's when we're trying for kids - and I don't think that's old at all!
My birth-father has two more daughters with his wife, and they're 15 and 17 years younger than I am. A few times that I've been out with my B-Dad and my sisters, we've been asked how old OUR daughters are. My B-Dad likes to respond, "Well, that daughter's 10, that daughter's 12, and that daughter's 27."
He gets such a kick out of the reaction that gets!
My birth-mom has a picture of me on her desk at work, and sometime a new employee or trucker asks about it.
NE/T: Who's that?
Bmom: That's my daughter.
NE/T: You don't look old enough to have a grown daughter!
Bmom: Thank you. I'm not.
(for the record - my birth parents were in high school when I was conceived)