Age of Names

Is it just me, or are there certain names that are meant for old people and certain names meant for young people?

For example...I know a lady who's 85, and her name is Doris Lacy _____. Today, I was imagining that when she was younger, perhaps she went by "Lacy" because, to me, that sounds like a young name.  If that was, in fact, the case...at what point did she decide, "I'm too old for 'Lacy'. I think I'll start going by 'Doris'." She goes by "Doris", now, and I just don't think that "Doris" is a young person name.

Okay...and my name. Kimberly, Kim, Kimmie...all of those sound young...and I don't even have an older sounding name to switch too! Unless...I go by "Kay" when I get older...which...I guess would work...but at what point do I start using that?!

Am I insane? Why would I even give it that much thought?

Oy.