It might seem that way (being over controlling) but, it’s your kids and it’s important you train them the way you want them to grow and so, it becomes how they model their life.
Kids are such a handful but, it’s the job of a parent to contain all their energy and curiosity.
A little more exposure isn’t always a bad idea and am not talking about gambling here but, social life. Letting them experience certain things breaks the gaps or adrenaline that pushes them to try out certain things when they finally get opportune.
When it comes to gambling it's obvious that 18 years is the minimum required age for anyone to start gambling, and as long as they are below the age of age of 18 they shouldn't even get a taste of it because gamble can sometimes have emotional impact on our lives which children below the age of 18 aren't ready for. You can have them experience some other things but not gambling while they are still young. Though some children are smart and would understand that truly gambling is not a good practice for them but others out of curiosity would want to sneak and play, at first they might see it like every other game but slowly it consumes their consciousness and they'll want to keep playing.