Soccer Reg Workbook

I have a spreadsheet for soccer with an a column if they are returning registrants. If I mark an x in the column it means they are coming back. In column e I have a kids birthday. I want 2 things.

1. When I enter the kids birthday in column e I want it to give me the age group in column c. For example if a kid was born in 2007 the kid would be in the u4 age group, if the kid was born in 2005-06 they would be u6, if the kid was born in 2003-04 the kid would be u8 and so on.

2. The other formula I wanted to know would be with regards to another sheet in the workbook. I want a formula that returns a count if I mark an x in column a that returns the age group from column c. Then when they register all I have to do is put an x by there name.

Thanks,