I still don't understand the concept of being protected "one time" in terms of birth control pills. Do you mean "immediately"? Once you are protected, you remain protected until you stop taking them for good. You are still protected if you have a 21 day pack and take the 7 day break.
Regardless, you can start your pills now but you will not be protected until you have been taking pills for at least 5 days or more. Give it 10 days to be sure. Just use a condom in the meantime. Normally you should wait until the day your bleeding stops. What's the hurry?!