I have a question bc I Got tri lo sprintec birth control pills

Sooooo, my period ended Saturday and I just went to the doc got the pack of pills today, my first time on any birth control. She said to start it Sunday but, now I’m thinking, must I ? Can’t I start it today? Bc Im meeting up my boyfriend this Friday and only until Jan 6. And the pill takes at least a week to go in affect meaning it would work Dec 30 even though I will begin to be sexually active the 22 till the 6. HELP