Ahhh first time mummy worries, I totally understand! Honestly, size predictions from scans boleh vary quite a bit, especially depending on positioning and the technician, a few of us had similar situations and our babies lahir perfectly normal weight, so don't stress yourself too much yet lah. The best thing is to discuss this directly with your doctor at the next checkup, ask them whether they want to monitor more closely or if it's within normal range for your baby; doctors akan know best if there's anything to worry about or if it's just how your baby's growing. Wishing you all the best with your pregnancy!