Cave diving requires special training. In beginning dive training they harp on you to never go into caves without training. It requires training and special equipment. Cave diving instructor would even even accept a kid that young for training. They simply dont have the experience to survive an incident.
One wrong kick of your fins and you stir up the much, turning the water from crystal clear to completely blind. They don’t have a reel on their suits in that picture. You have to strong a line from the entrance all the way. So you can follow the string back if you get lost.
Highly experienced cave divers die all the time.
I have been diving since 1994. I am NOT cave certified nor have and desire to get certified, and will not get anywhere NEAR an underwater cave!