Here in the uk a child must start school in the academic year he has his 5th birthday (the academic year starts in sept) so most children are 4 or 41/2 when they start in sept and at some point before the following sept will have had their 5th birthday so our yr groups go like this:
Nursery from 3 but not compulsory
reception: will be 5 during the school year
yr1: will be 6 during school year
yr2: ” 7 “”””
yr3: ” 8 “”””
Yr4: ” 9 “””
yr5 : ” 10″””
yr 6: ” 11″”””
These all comprise what we call ‘primary school. Then they go up to ‘secondary education’ or secondary school
yr 7: ” 12 “”
yr 8 : 13
yr 9: 14
yr 10: 15 this year andthe next (yr 11) are for their exams GCSE’s
yr 11: 16
at this point the child has taken his gcse’s and can either leave school or stay on for 2 more years to do higher education normally ‘A’ (advanced) levels. which they then use to get into university.
yr 12 (lower sixth form): 17 yrs old
yr 13 (upper sixth form) 18 years old
I don’t know how your higher education works or when they ‘leave’ school. Here as you can see, they can leave at 16 years old or stay on for another 2 years and leave when they are 18 ( although i believe they are in the process of reforming this so that they have to stay till they are 17…..)
How does this line up with american grades?