Knowing your credit score is not the same as access to your three credit reports. Your credit score is often called a FICO score. It is taken from information on your credit reports and general data on all borrowers in your area. FICO is an overall grade.
You can purchase a copy of your FICO score at myfico.
Just as your credit reports change as you use credit, make payments and apply for more and different types of credit, so your FICO score will change from month to month.
Look in the Blog section for Categories labeled Credit Score for ways to improve and sustain a good FICO score