I thought it was ours -1 so year 9 = 8th grade?
I'm 99% sure that the USA is the same as here in Canada.
So it goes:
(possibly preschool when 4 years old) kindergarten at 5 years old, grade 1 through 12, age 6-18 (could be 17 if you are born from june-december)
so I assume kindergarten = year 1, grade 1 = year 2, and so on.
Also, I am in grade 10, I play video games often, and get straight A's. Being in high school does not mean you will spend all of your waking hours studying lmao. I have exams in a week, and will probably study for like 2 hours tops, and get good marks. Don't sweat it too much.