There is a book out called Why a daughter needs a mom...its kind of a sentimental sayings book that is written for the grown up daughter...
For my daughter's graduation, she's getting that and also a scrap book of all her awards, pictures, etc in it...I've been working on it for a while now...
For my son's 21st, I took him, his gf and 2 of their friends (even tho about 20 showed up) to see a movie (Avatar) and then we went (about 12 of us) out to eat and I bought him a drink...lol The significance of that is...he doesn't drink (by his choice) but you can't have a 21st without something to celebrate with... :)
My daughter's 21st...now that's a different story...for that day...me and her are going somewhere...just us...to walk and talk and shop and lie around...and just be. That's my plan anyway.
I LOVE LOVE the idea that some of the mom's have of giving them their first "adult" gift...coffee table book of art, art for the walls, set of glasses, etc. And the one that suggested the gift cards...EXCELLENT! You can start now and get one a week til her bday and organize accordingly.
For my son's graduation, I gave him 18 $20's, individually wrapped in boxes, inside a box that was inside a box that was filled with confetti. Vacuuming was fun. Watching him open 18 boxes was even better...lol
Sending good thoughts your way...