I'm sure you are getting varying opinions here. My kids have done sports since they were young. I let them choose what they want to do and because it is a team sport, I tell them it's not fair to their team to quit! BUT, if they had ever been truly unhappy, I probably would have let them. Can you ask her to try for a little longer and maybe play a game or two to see if it gets better?
My son played trumpet and we paid for lessons, paid to get the trumpet tuned and did all we needed to, and he did not like it! He has braces and found it was a LOT harder than he expected. I made him continue to try, but finally gave in and let him quit before his first concert. He was unhappy and wasn't giving his full effort anymore.
Watch your daughter and see how she does at practice and games. If she seems truly unhappy all the time, it might be time to just eat the cost and let it go, but have a heart to heart to her next time she wants to do a sport. She doesn't get to quit! Good luck w/ this...keep us updated! I hope she starts to like it!