R.V.
Really talk to her about it as often as possible before you go. Make it sound exciting and lots of fun. If she likes watching you get ready talk to her about how you get your hair done (trimmed, cut) so you can get ready everyday.
Our son had his first hair cut at about a hear old. He hated it and now it is a treat for him. We tried the kids place too and it didn't help. Th place was very busy, there just seemed to be too much going on and some of the other kids were screaming and crying. We now go to the local shop and he is usually the only one there when we go so he thinks it is special just for him. We spent a lot of time before his second appointment getting him ready and really pumping it up as a very special thing. The local shop also sent a small cape home with us so he could play with it and get used to wearing it. We always have a treat of some sort after, either a sucker or we go to the park or play with his trains.
Take your camera! If she likes getting her picture taken you can use that as motivation too.
Good Luck!