EDD na nagbago bigla

LMP = MARCH 11 LMP EDD = DEC 16 FIRST ULTRASOUND EDD = JAN 2 (transv on 7th week) 4D ULTRASOUND EDD = JAN 10 regular ang mens ko mula january dahil naka pamparegla ako non ( irreg ako before due to PCOS) should i follow LMP o first ultrasound? Salamat. FTM.. para lang sana alam ko kelan ako mag mat leave sa work. SALAMAT