Are they your credit cards with your children's names on them? Or are they your children's credit cards?
Seems like it would have to be the first as they are not yet old enough to legally sign a contract.
And just as an aside, it's my belief that 14 or 15 is too young to handle a credit card, especially depending on what the credit limit is.
Your two may be mature enough to be the exceptions to the rule but taken as a whole that age group isn't ready for credit cards, bank loans, or used car buying.
These cards have their names on them. Also, they have TX state issued picture IDs so they can use the cards (they are actually debit cards).
I know my oldest uses his card every so often so I'm not sure about being old enough to sign a contract....