Here is the age of your child in April 2020 that you can take a cue from and decide if your child is fit or underage for a class:
2 to 3 Years should be at Home.
3 to 4 years should be in Nursery.
4 to 5 years should be in KG.
5 to 6 years should be in I.
6 to 7 years should be in II.
7 to 8 years should be in III.
8 to 9 years should be in IV.
9 to 10 years should be in V.
10 to 11 years should be in VI.
11 to 12 years should be in VII.
12 to 13 years should be in VIII.