question about due date

Bunny • ttc 4 years with 2miscarriages. Rainbow BABY GIRL born 3/10/18💕🌈 Gorgeous girl#2 born 02/19/19💕💕 baby #3 due 03/01/21

so my last period was june 2. i ovulated on june 17, & i was expecting my period july 2. but do i base my weeks off a 28 day cycle or when i was actually supposed to get my cycle?