As far as a gift, I'm not much help. I have a daughter turning 19 this weekend myself. I'll be buying her hunting license as part of her birthday present... not sure about the rest.
I do have a suggestion, since yours is hitting a milestone at 21. Last year about this time, my family was going through some difficult weeks and months. I heard a gentleman on a Christian talk radio program talking about the value of writing letters to your children. I did this for my 3 daughters with 2 purposes in mind. 1) Admit my shortcomings to them as a father, husband to their mother and leader of our household and to ask their forgiveness. 2) Affirm them and assure them of their value as individuals, as my daughter and as a part of our family.
This required me to think and pray about my family and my children individually in a deeper way than I was used to. I noticed the other day that my youngest daughter has her letter taped to the back of her bedroom door, where she sees it every morning and every evening.
Although your situation sounds much different than mine, I suspect there would be deep meaning attached to a letter to your daughter that would be a real blessing to her in the days and years to come.
