Little to no credit is bad credit hence your score. Most banks will also require some installment loan history to approve you, ie personal loan, mtg, car note, etc... A credit card is a good way to get started, but if your looking to increase your score, go take out a $500 personal loan or whatever your banks minimum amount is. Take that $500 and pay down your CC with it and than make the payment on the loan. Yes you will be paying interest on that money but you'll also see your score skyrocket within 6 months. Im 24 with a credit score of ~750 and work for B of A as an underwritter and review credit all day long. I know what im talking about.

 

U make 24k a year, and your looking to finance 36k. That a 150% debt to income ratio. Thats why! 620 score is NOT good, you credit file is probably to thin to be able to get a 36k loan.