Cannot Change Date of Birth after entering the first time

Once a student is added and the DOB is entered the first time, parents cannot go back and change the DOB. If they entered wrong and we do not have the correct DOB on file, they will have to contact us and we can change it on our end, but they can't change it on their end. We are seeing more and more parents trying to abuse our age cut off to enroll their dancer in the class they want instead of the class that is correct for their age group by adjusting their DOB to whenever they want. Hopefully, not allowing them to adjust their age in the system will prevent them from falsifying their dancer's DOB.