women in their 30s are NOT old ladies

The other day I was taking the subway home with my 24-year old co-worker.  She started telling me this story about her mom's "old lady" friend.  When I asked how old was old, she replied "in her 30s or 40s".  Whoaaa... backtrack.  Since when were women in their 30s and 40s considered to be "old ladies"??  Me, being in my late 20s, totally resented her statement and had to correct her on the spot so she wouldn't go around offending other people.

Yesterday she stopped by my desk and said "okay, I got it".

Me: Got what?
Her: I know the term for women in their 30s
Me: What?
Her: Middle-aged women

I swear I could've killed her.  I don't know about her but I plan to live until I'm 88 and half of 88 does NOT equal somewhere in your 30s!

Her: Fine, so what's the proper term then?
Me: I don't know right now but it's definitely not THAT!  I'll think about it and let you know.
Her: Fine.

*sigh*

What can I expect from someone who doesn't even know who Donna Martin is, or who can't name a New Kids song from the 80s, or barely remembers The Cosby Show?

Youngins these days kill me.