Congrats sa first ultrasound mo, mama! Generally, ultrasound is more accurate especially ngayon na nasa 2nd trimester ka na, ang dating estimate based on LMP ay pwedeng off by a week or two, but ultrasound sa second trimester is super reliable para sa exact dating. Ang best talaga is kung magkasunod ang both, pero if may discrepancy ka, usually doctors go with the ultrasound reading na ngayon since nakita na nila baby mo in person, so mas accurate talaga!