The lady was probably just trying to make conversation - that's what we old(er) people do sometimes. I really don't think she was trying to be rude. Sometimes people just "don't think" before putting their mouths in gear.
I think "expected marrying age" changes from time to time -
If one wants to be married at 21 - fine. If one does not want to be married at 21 - that is also fine.
We are so fortunate that females now have so many more choices about how to live their lives.