The youngest mother on record was 5 years and 7 months old. Yes, you read that right.
And it didn't kill her, either, contrary to the knee-jerk reaction of many on FR. In fact, she's apparently still alive today. Her son died a few years ago at the age of 40.
This is a clear and definitive case of life of the girl, you would risk her life for something she would barely understand if at all? You are stating the exception that prove the rule.