Joseph: the legal minimum age to marry in Guatemala is 18. But they have indigenous poplulations that basically ignore the ban.
Which brings me to the real answer. Guatemala has a starving, poverty stricken population and problems on a much larger scale to busy itself with a cult that needs resources to ascertain if they are violating the law, and additional resources to find homes for the kids and prosecute as needed. Assuming they even care.
We can’t expect a third world country to act like the US would.