first timer 😬

hey! so i had gotten the depo shot in December and and i was due for a new one, i decided i wanted to be on the pill. ive never had it im new to it, my doctor said i can start taking it when i get my next period; I started getting the brownish blood as if i was at the end of my cycle and it stopped today, April 14th, it lasted 3 1/2 days, I don't know if it would be considered a period and i should start taking the pills... any advice?