Yes, get the 504!! Make the teacher and the administration educate themselves on the rules. The plan is so that your child can accomplish the same goals as the other kids, but with a little more time. Do not let them cheat your child out of grades, recess, lunch, ANYTHING.
I know teachers are busy, but she could set an alarm on her watch/phone/computer to remind her when it's time for your daughter to go take care of treatments, etc. I do agree that your daughter could probably handle the responsibility to remember some of this too. You might be surprised at how well kids do when given the chance. Good luck.
Stacey