Hindi na maalala ang last day of menstruation

Hello, mommies. Currently on my third trimester and pinaulit po ng OB ko yung bps since may discrepancy sa date ng last menstruation ko. As far as I remember October 2024 po last period ko and hindi ko lang matandaan kung ano yung exact date. Possible po ba malaman sa bps yung supposed date of delivery ko? Hindi po ba ako sesermonan ng sonologist kapag hindi ko po mabigay yung exact date of last period ko? Thanks po, ftm here.