> In the U.S. it is illegal to offer credit to anyone under the age of 18 as they cannot legally enter into contracts
Minors can legally enter into contracts. Those contracts are entirely binding on the non-minor party. The minor is the one that can repudiate the contract before the age of majority to void it, but otherwise, it's a perfectly valid contract. If the minor remains bound past the age of majority, the contract can no longer be voided, either.
There are credit cards marketed directly to teens.
Minors can legally enter into contracts. Those contracts are entirely binding on the non-minor party. The minor is the one that can repudiate the contract before the age of majority to void it, but otherwise, it's a perfectly valid contract. If the minor remains bound past the age of majority, the contract can no longer be voided, either.
There are credit cards marketed directly to teens.