An FHA loan will not penalize you for her lower scores.... 620+ gets the same rate as everyone else. But she will need to be over 620 for most institutions.
Quite simply, you should apply.

Your high scores will help the deal quite a bit.

http://dallasloanguy.com/docs/about_credit.pdf
For future reference, here is a link to a free e-book about credit that may be of interest.

Good luck!
Feel free to contact me with any follow up questions.
Tom Burris
DallasLoanGuy.com

You need to have atleast a 620 credit score now for FHA. If your fiance is below that you will be out of luck, you will not be able to use her income. YOur best bet is to talk to a mortgage professional that you trust, not just someone from the yellowpages. If her score is below 620, you can still qualify with your income or you will need to spend a little time and get her credit fixed to it is above 620, which unless its really bad, should not be that hard.

Defintely speak with a local lender.

With regards to qualifying, lenders make their decision based off of the lower of the two applicant's credit scores. Great credit on one side does not offset poor credit on the other side. So if your fiance's credit is not satisfactory (at least 620 for her middle score) then you will not be able to use her income towards qualifying.

Talk to a bank to see where you are at now, and if the timing is not right then do what you need to do to get her credit in shape to give yourselves the best chance of both qualifying for this loan

Best of luck!

FHA Loan programs are some of the most popular loan programs available now because they offer flexibitity when it comes to credit. FHA is a make sense underwriting platform which means if you pay your bills on time or have a very good explanation as to why you missed a couple of payments then an FHA loan will most likely work for you.

This first step you need to take is to get pre-qualified for an FHA loan. You do this by completing a loan application and pulling a credit report. With these two items I would be able to tell you when you will qualify, for how much you quailfy and at what rate. This can be done via our website.

Now is a great time to buy a home, rates are very low and if you are a first time buyer you can get up to $8K from the government once you buy your home. Chris if you have some time please go to my website and look around. There is a good chance that many of your questions will be answered there. My contact information is on there as well so give me a call and I will be happy to answer any questions you have. I hope this was helpful and I look forward to speaking with you soon.

I would recommend that you contact a local mortgage broker, or bank. They will explain everything regarding the FHA process. That way you will be able to ask them all your questions, and they will give you solid answers.