I was reading an old newspaper here and came across a sad story. I scanned the story into my laptop and will let you read it here. Click on the link above.
As you can read, some of the kids were not in school even though they were very young. You will also notice how vastly separated the one who are in school are in grades even though they are about the same age.
Though it is not common, it is not rare here either. I think it was one of the house keepers we had a couple years ago who said her mom was pregnant when she was only 14. The house keeper said she left home because if she stayed her parents would pressure her to get married and help support them. She did not want to end up like her mom.
Previous to this year kids graduated high school at 16 years of age. They just instituted a K-12 policy but of course that means grade 11 is the highest so far.