1st pregnancy

Hi pls. enlighten me. Last period ko is Dec.16,2018,and by January 2019, nag aabang ako na magkaperiod, since di naman ako nadedelay kasi regular ang mestruation ko. Pero wala, until now February. I have a feeling na baka preggy ako. And I took the PT this morning, its positive. My question is kelan mag start ang count ng pagbubuntis ko? Pls. bare with me, its so new to me ? TIA :)