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As a new credit score goes, that is quite acceptable!
I offer a few things to keep in mind as one with a brand new score, and short credit history.
Yes, both short history and limited number of accounts is initially a negative in credit scoring. FICO is a risk analysis based on determining your liklihood of being delinquent in the future based on your past credit history. With a short history, and limited number of accounts upon which to assess that risk, naturally, their algorithm looks a you skeptically.
You cant do a whole lot about your age of accounts other than to let them age. However, in building for the future, you definately need more than one revolving credit account (e.g., credit cards). FICO scores your use of revolving credit higher than other forms of credit primarily because it is discretionary on your part, as you set how much of your credit limit you utilize. This will move you from what is called a "thin" or "lean" credit file into a more favorable "thick" credit file. A credit line increase is not as useful as a new cc because FICO does not directly score your CL, it scores only your percent util of that CL. You need multiple revolving accounts to move into a thick credit file, showing that you can handle multiple discretionary accounts.
Percent util is not that critical when you are in a credit building mode. Sure, keeping CL low will help your score, and tweaking it by keeping all accounts under 10% is ideal. but that is a lot of monthly work. Percent util has NO historical memory, meaning your util next month erases, as far as FICO scoring goes, whatever it was last month. You want to be concerned with maximizing your score just before you intent to apply for new credit, but in the interim, it is not that critical.
The absolute most important thing when building credit, and in fact at any time, is to NEVER, EVER have lates. FICO views delinquencies and derogs reported to a CRA as one of the most important indicators of the chance of future delinquencies, and thus they hurt your score more than anything else.
Then build a file of at least 2-3 revolving accounts. While you will have to apply for new credit to do this, and thus take a short-term, and small, hit for new credit inquiries, and each new account will keep your average age of accounts down, you need to do that to have the accounts in your credit file upon which to build age. Try to keep your new inquiries to only those for which you actually want a card. Getting new cards will take some time, as some degree of credit history will probably be required to get the better cards, so take it slow, and build up to the bank cards. Secured cards and cards issued by a credit union are a good place to start.
