There is a wide range of available loan programs for people with various credit scores. If you are thinking of beginning your home search, it may be worthwhile to pull your credit and see where you are. If there are any errors, you can start working on the corrections.
The lower your score, the fewer options you will have. It won't mean that you cannot buy a home, but you might have to buy a lesser priced home if the interest rate purshes up the monthly payment. A lower score does not mean you cannot buy, but you are higher risk and therefore will receive a higher interest rate. After a year or two of good payment history, you can refinance for a lower rate. If you have very good credit, you will get more favorable rates, and have more options.
There are programs available to help first time homebuyers, and these vary by geography. Search the internet for those terms to find a Realtor who is more famiiar with the programs available in your area. There are also grant programs that might be available in your area. Nehemiah is one example, and they are national. Contact Nehemiah to find out if there are any homes in your area. There are other programs similar to Nehemiah, but do check out their credentials.
Your best bet is to find a lender and realtor who specialize in that market. Check your local library for any seminars. In some areas, libraries allow the use us of meeting rooms for seminars for that purpose.