Also, prior to doing the proper character applications, there's a mistake (An easily done mistake, that is) that everyone has made. Because Hogwarts' school year starts in September, a lot of characters ages, birthdays and school years don't correlate. To clarify:

If in the Fourth Year, your character will either be 14 going on 15, or by some rare chance, has their 15th birthday on the first day of term, meaning they are the oldest in the year and also 15 at the start of the roleplay. All others, who have their birthdays in December, March, or June, will not be turning 15 until those months. Therefore, your character's age should be 14 if they are in fourth year.

For the Fifth year, the same thing applies. Your character will be 15 going on 16, or by some rare chance, have their 16th birthday on the first day of term. You get the gist. If many people are wanting their character's to be 15 - as I can see from the applications - then they will be Fifth years, not Fourth. If you would like them to be in the Fourth year and have their birthday in the IC, that is also fine - but for the time being, they will not have hit that age until their birthdays.

I've made that as clear as possible, so I hope you guys understand - it can be a wee bit complicated.