Thats right,my wife did not have long hair when i met her.(shoulderlength)
I knew about my fetish,but i told her only a few weeks later.
I know i was lucky enough to have met a girl who had no problem with that.The last trim she had was on our weddingday.
After that i had to cut it 2 x (we are married for 13 years now on august 20th).
She even helps me with my ponytailcollection.
What i want to say is that take it easy with your hairfetish in the beginning but let her know from the first day that you like her for who she is.And make compliments about her hair,but don't overdo it !
Good luck,really hope you succeed !!!!!