Gifts are very personal, think about a time you saw her happy and smiling? What were you doing/talking about? If you go for jewlery think about the meaning it could send, how about watch with the date ingraved.
Don't do any thing that puts tons of presure too get way out of her comfort range, no black tie if shes a jean girl.
You could do a beach day and stop by the casino have dinner. No presure and she can drink,dance, gamble.. you know all the sfuff that she is now legal to do.
Daughter bar hoped all over town said if was good.
Son went to Vegas and said it was good.
Its all in the expectations.
Sorry I'm in the old group,
Beckie