Is that better or worse than a girl who refuses to even let you buy her a vibrator for her 18th?
Among my friends, that were not interested in bdsm, fluffy handcuffs did the trick for a present. And they are cheap in a sex shop.
Probably she has some personal thing about vibrators - she links them to lesbians or masturbating.... I had the same problem with my presents. Also if you are not sure she would be ok with you to use it to her, better not give her such present yet.
You can buy her something cuter, smaller, and maybe wear it on public (I did but I cound't convince her yet to wear in public but the gift was very ok): a butterfly clit stimulator like
http://cdnimg.visualizeus.com/thumb...ulator-ee73e9c8ad07412524c12a8d589519f0_m.jpg You can ask her to wear while making love.
Or if you have sex you can buy her a vibe ring and keep it for a good romantic night. It doesn't arouse you very much (usually the vibrating part is at top root of your penis to stimulate the clit). You can show her and ask to try together.