Put some serious thought into this. Braiding is very damaging to your hair. It also exposes much of your scalp to the sun and makes it very likely to get burned - not so fun with the pain and the peeling that comes afterwards.
If you have very healthy hair now, I would avoid this and keep the healthy hair.
I have long hair that they would love to get their hands on, but once I talked to a couple of hair stylists, they have given horror stories of the outcomes.
Just make sure that you know what may happen. I am not trying to talk you out of it, but just make sure you know what you are getting into.