Sounds like you are sending a paper application in. If you want some un-asked-for advice, I suggest you submit your application via the AADSAS website. Its more secure and really easy to use. You are almost guaranteed to not miss a section when using it, on the other hand, paper can get really confusing and you might forget to mail a page in.
Now, if your still interested in sending a paper application in, I think the font size they want is 10, it should say on the instructions section. If its too long, edit it, if what you take out is good, what you leave in will be GOLD! GOLD JERRY!