As Lori was saying FHA has made a tremendous come back and we will be seeing a lot of these loans in the upcoming months. FHA does offer 100% loans using the Nehemiah down payment assistance program, which may help you being a first time home buyer and all.
FHA is not so much score driven as conventinal loans and usually anything above 620 will usually get you a loan, My lender has done loans with FHA for my clients that have only had a 580 so it can be done, but of course please speak with a lender and get their advice.
Also, being a first time home buyer you do want to hire an agent to work on your behalf. There is no charge for this service and they will be able to guide you through the entire buying process because the last thing you want to do is have to worry about what to do next. Hire a reputable agent, sit back and enjoy the home buying process. It does not have to be a stressful situation whatsoever.
Good Luck in your new adventure and Congratulations
With you being a first time homebuyer, I would suggest that schedule a no obligation consultation to learn about the home buying process from a well qualified Realtor... it needs to be education not a sales pitch on why you should use them. There are home buyer seminars also which needs to be educational and not a sales pitch.
A well qualified lender can tell you exactly what you need to to do build credit. Based on that question I am assuming that you have no credit history. I would recommend that you contact a reputable lender and consult with them as to what you need for your credit to qualify to purchase property. You might be surprised as you might be able to qualify for a FHA loan.
FHA is liberal on credit scores so you can have a lower score but they do require that the previous 24 months of credit are clean.
680 or above is considered a good credit score but again FHA allows for scores below 680.