Hi. I Have Not Been On Birth Control And My

hi. i have not been on birth control and my period was 5 days late, i did not want it to happen as i had just gotten birth control pills from my doctor. so, my question is i started my pills 5 days ago and as of today am technically 10 days late, would my pills have kicked in quick enough or is it time to bite the bullet and get a pregnancy test?
thank you