I'm inclined to agree.This act certainly suggests...*strongly* suggests...that this young woman is worthy of high respect the fact that this much of a fuss was made about it is an indictment,not of the kid (I call her a kid because she's young enough to be my grandchild) but of our society.
I'm pushing 70 yet when I see an older person,a person with an obvious disability,a pregnant woman or a woman with a young child on the subway I get up and offer him/her my seat...while far younger people stay seated.
Does that make me a hero? Most assuredly not.But,IMO.it does say something about how kids have been raised in recent years.Of course I'm not including this young woman in that "indictment".I can easily see her doing the same thing I do.
This important things I always apply to those situations you just described.
1) You did the right thing
2) You set a good example for others
Carry on