Now that realistic aging has been implemented on the sites, a lot of 6th year students will be turning 17 soon. In the books, Apparition class can be taken before one turns 17 and the exam as soon as one turns 17 - they don't have to be 7th years, as it is on WoP.
My suggestion would be to allow an age requirement, just for Apparition, so anyone who's 17 years of age can take Apparition classes. See the example I created below! I think this would make it more realistic, especially now that aging has changed to be more realistic, too.
Customer support service by UserEcho