This simple Mortgage Calculator can help you figure what your payments will be on that first home.
Just enter the figures requested, amount of loan, interest rate, points to be paid on the loan if any, and the number of months for the loan (i.e., 30 year is 360 months).
This loan calculator will then figure what your monthly payment will be, the total amount of interest you will pay, and the cost for the points. Finally, its gives you the total amount you will pay for that fixed rate mortgage (which is the principle and interest combined.
Sometimes its surprising to see how much you pay in interest over the length of the loan. As a first time home buyer, you may want to think about extra principle payments. Or shop for a lower interest rate.