Your mortgage rate will depend greatly upon your credit history but also upon other factors such as your debt to income ratio and how long you have been with your employer. If you are a first time home buyer the lowest mortgage rates you can expect are still going to be a little bit higher than others if you are not making a sizable down payment or paying points on your loan.
The lowest mortgage rate you can get for your loan will only be realized if you strike while the market is ripe for purchases. As recently as the early 80s rates at more than twice todays going rate were considered excellent. Buying a home is a big step away from renting that requires more financial stability. However building equity in your home can be invaluable for financing loans in the future and giving you the support you need to take care of your family.
To assess the lowest rate you can get on your mortgage a broker will run a credit check using your social security number and that of your co-borrowers typically your spouse. Another important factor in addition to your credit score is your debt to income ratio. Even if you have particularly good credit, if you are carrying a lot of debt your loan will be perceived as more risky by the lending institution and it may limit the amount you can borrow.
To get the lowest mortgage rate possible you will want to consider paying points on your mortgage. Points are typically equal to one percent of the total mortgage. By paying points you can get your interest rate lowered by as much as a couple percent. Typically this is not an option for first time homebuyers because it is difficult enough to come up with the money for a down payment.