Is your "credit score" a FICO? If it is from Credit Karma, and the like, it is a VantageScore and is not indicitive of your true score.
In what way are you being given a "hard time"?
Auto loans are typically based on an auto enhanced score.
Credit Unions may use a different score I know DCU so I talk about DCU. DCU uses FICO Equifax Mortgage score. In my case it's 20 points lower than my FICO Equifax 8 Score.
Dealers and captive financing (Ford, Toyota, BMW) typically use an auto enhanced score. Having positive previous paid auto loans will help that score, not having that will hurt.
Also you list 1 score and not the source so we don't know if it's Credit Karma Vantage score. At times I have seen my Credit Karma scores be 120 points higher or 120 points lower. There are lots of differences in how they calculate things.
So we don't know what your score is with regards to what matters for financing a car.
We also now know that you are new to credit with a very thin short file less than 1 year.
So the dealer is complaining that your credit is too new.
Perhaps try the Capital One Auto Navigator (just Google it) maybe they can pre-approve you. Just know if you go past the pre-approval they will run hard inquiries on all 3 bureaus.
You can also try and get a loan where you do your main banking. The banking relationship can really help sometimes.
Also keep in mind that it's easier to finance a used or certified pre-owned car CPO than a brand new ones because new cars depreciate so quickly. Also often times a CPO has a better warranty than new. Mine came with 46 months unlimited miles versus 48 months 50,000 miles.
Since your file is thin adding a loan will definitely help you. See if your bank/credit union has a shared secured loan. This is a loan where your payments go into a savings account you cannot touch then when paid off you get the money. This will help your credit mix by showing a positive trade with an installment loan. That's not instant gratification but good credit is deeper than the score and taks time to build.
Maybe also consider putting in a credit app online with the brand (Ford, Toyota...) Maybe you can get approved online and not worry about the dealer.
Whatever you do learn from my mistakes and others on the forum do not settle for a high interest loan because that's the best you can do today. I did that thinking I would refinance in 6 months but the new car depreciated too quickly and too little principal is paid at the begining of the loan and I couldn't do it as the loan to value was too high.
If it is an emergency and you need a car today maybe try and finance something used where you can put 1/3 down.
Also your AAoA average age of accounts is based on all of your accounts so if your oldest Discover is 9 months and 2 more and new then your AAoA will be less than 4 months. Less than 1 year is really bad, less than 2 years not great.
Hope this helps good luck and definitely keep us posted.
The more info you give us the better we can answer like right now we don't even know what score you are looking at and since you didn't list multiple scores have you even checked your credit reports to make sure there are no mistakes/fraud? that's super important.
There are trials you can get cheap maybe $1 where you can get a tripple report with FICO scores then cancel before the monthly billing starts.
If you are going to wait the year then in the meantime get a shared secure loan that will show as an installment loan and help your score.
However Boone is right other dealers like Ford might be easier and don't rule out Capital One Auto Navigator and credit unions.
Capital One will give you a car loan. With your file/score you will get a reasonable rate. Here is the link. Prequalification is a soft pull.
Depends on what you mean by easier. Every lender I have ever come across charges higher interest on used cars compared to a new car. That is because a lenders main concern, if you do not pay, is how easily they can recoup value. All things being equal, the newer the car the more it will go for at auction (which is where repo car end up).
Also keep in mind that it's easier to finance a used or certified pre-owned car CPO than a brand new ones because new cars depreciate so quickly.
It's actually easier to get a new vehicle than preowned I work at a car dealership banks and lenders are more willing to do a loan on a 0 mile vehicle with warranty than a preowned and typically offer a higher apr on preowned as well. Good luck on your vehicle and more than likely it was the length of accounts but there are many factors that play into an approval or denial when it comes to vehicles.