More than zero. How often is it acceptable for a 12 year old girl to be married off to an adult?
I’m not convinced it is more than zero. Do you know of a single case in the 21st century of a 12‐year‐old marrying an adult in the United States?
After all, you rhetorically mentioned America in the same breath as Afghanistan, where 15% of women were married below the age of 15. (page 11: https://www.unicef.org/afghanistan/media/2711/file/afg-repor...)
Oh well done. America only allows men to marry half a dozen 12 year olds in the 21st century. It’s better than Afghanistan. Have a medal.