Question:
Hello.
What a thoughtful idea for your daughter's 18th birthday! I personally think that you should buy samples off eBay, put them in a box, wrap the box, get a birthday card and write that you're going to buy a full bottle of the sample she likes the most. If you do this you'll buy something that you're sure she will love and use.
Unless you know what a person likes or already wears it is difficult to shop for them. I once had someone buy me a bottle of D&G Woman and although I do love woody scents, this one did not work with my chemistry - in fact it worked against me. I smelled like cat pee! I had to give it away to someone that smelled terrific wearing it. I can only enjoy D&G Woman vicariously now.
Hope that helps.
P.S. The Body Shop sells a sample pack. So do some etailers like dragonflyblue (not affiliated)... etc.

Answer:
What a nice mum -I may do that too in 12 years. I have D&G Light BLue and my 6 yr old daughter likes it she occassionally has asked for spritz. It is very light and Spring like, similar is Raplh Lauren's Ralph. I also tested Miss Dior Cherie it is fruity a bit sweet, but it seemed rather young to me, its has strawberry in it, and when I was 16 I used to wear Body Shop Strawberry oil, and I always received so many compliments. Body Shop White Musk is nice light, young. Perfume is so personal its soo hard to buy for someone. You could purchase a few dozen samples from ebay or somewhere, or keep going back to the dept stroes and asking for some. One thing though - I wish I had not thrown or given away all the perfumes I did not like when I was younger as my tastes have changed. Do they really go bad after awhile? Good Luck

Answer:
How you smell is such a personal thing that I have a hard time buying a fragrance as a gift unless I already know that they like it. I faced a similar problem with my younger daughter turning 16 and wanting to get her started on a fragrance wardrobe.
What I did was I collected a bunch of fragrance samples, I think I got about 40, and told her to test them and that I would buy her what she wanted. I view that as something of a double gift as she has gotten the chance to explore a number of different fragrances, plus she got a fragrance that she would be happy with. With minimal effort I was able to collect the 40 samples in about a month.