Question about the hiring process with the school system

I have my teacher assistant certification and I applied for an 'Anticipated vacany' back in the end of July to a school district upstate...any...I hear nothing. I get a card in the mail saying that my resume was received and if thers an opening they will call me, if not they will hold onto the resume for 6mths blah blah..anyway..I call and the receptionist tells me they are still reviewing applications (this is towards the end of Aug beg. of Sept)...is this the norm? My mom (who works at a school) says they first have to evaulate the kids and see if there is a need and how much of a need for teaching assistants is necessary...that they may even call towards the end of Oct. Is this true? How does it work in ur shcool?

Thanks ladies!