On a first credit card, how long until my credit starts to be affected?

I got my first credit card a little over a month ago, and am very anxious to start building my credit score up.
I have already made my first payment, on time and in full, and my next statement should be arriving within a few days.
I have heard that you have a 3-payment-cycle “grace period”, in which your payment habits do not affect your credit. Is this true? Or does your credit start being affected as soon as you make your first payment?

Creditors report to the Credit Bureaus every month. Your credit will increase as long as you continue making timely payments and keep your balances under at least 50% of your credit limit (30% is a better goal but 50 is ok). Although creditors are not allowed to report a late payment until you are 30 days late, you should still pay on time to avoid APR increases or decreases in credit limit that could affect credit negatively as well.