Hi mama! Postero fundal placenta lang yan means your placenta is at the back of your uterus near the top, which is actually super normal and a good position, walang problema dyan at Grade 1 means it's perfectly healthy at this stage of pregnancy! As for baby's weight, 180 grams at 17 weeks sounds right within normal range, pero since you're a first-time mom at may specific concerns ka, best ask your OB sa next visit para ma-confirm niya if everything's tracking perfectly for your baby's age. One of my mum friends worried din about similar things early on, but her OB assured her na as long as baby's growing consistently, it's all good, so don't stress too much, mommy!