Never too old......
My daughter is 15 and still does them, it is how they are presented, haha. She has confidence that they are cute and "cool" and it let's her friends know she cares.
As they get older, maybe she wants to do just her friends, not the whole class........
Also, my daughters high school does a fun thing where it is $1- and goes towards the school. you can send a Valentine Gram to a friend, It is basically a little card and a piece of chocolate.
They do this for eachother, again, friends only, not the whole shabang.
Tell your daughter, these things happen, one day she will give a Christmas gift and there won't be one in return, it is ok, it is about having fun and giving. We are all people here on this earth and she did a wonderful thing by sharing a bit of her "sunshine" with the class! Too bad the other kids are feeling they need to "grow up quickly" and not particpate, or look at it in ad odd way.
She did a fun thing and as long as she has confidence in that it shouldn't shake her, I say........." Do it again next year girl!"Put a smile on your face and deliver some love and sunshine to this world.
xoxo
T. B.