Visit our Pregnancy Store! ... Plus, young adults are highly probable to carry revolving debt and pay late, producing more interest and fees for the card issuers, she said. Card issuers also will need a co-signers approval to increase credit limits of a cardholder younger than 21. And issuers won't be authorized to offer T-shirts or trinkets to entice students. Some credit experts say students need a card to start building a credit history and score. ...