Aih, congrats on your pregnancy! Perut keras tu biasa je, especially kalau bloating or constipation, hormone progesterone tu memang buat stomach muscles relax dan perut jadi tegang-tegang. A few of my mum friends said the same thing early on, so you're not alone! But since it's your first baby and you're worried, best to mention it to your gynae at the next checkup la, just to make sure everything's smooth and put your mind at ease. Meantime, drink plenty of water, makan fiber, and try to relax, stress buat perut lagi keras. Take care, mama!