Car companies have the option to use FICO or VantageScore to determine the overall credit score of applicants. FICO scores below 640 are considered poor. VantageScore ratings run from super prime to high-risk, where scores of 600 and below are considered high-risk. Poor or high-risk scores tend to receive loan terms with the highest interest rates.
Even if you do fall into the 10-13% range now, it should be fairly easy to refinance your auto loan with the same credit union once your 622 credit score goes back up to say, 680 or above. Car credit is some of the best credit to have! One last thought, you'll probably only be able to finance $8,000-$12,000 as a first time buyer.