I say respect her wishes. if she doesn't want a party, then don't force one on her. Take her out and give her a wonderful time, just the two of you, or maybe just your immediate gang.
For my 16th, my GF took me out to a movie, then a fancy restau, and we went dancing afterwards. While this may not be the most appropriate evening for you and your friend, since you are not romantically involved, you get the idea...treat her to a great time, you know her best, you know what she would like to do.
Poetry is not pretty....poetry is real