Good night - we're not sleeping ? 31 weeks. Own average build, has som…

Good night - we're not sleeping ? 31 weeks. Own average build, has some fat on her belly... First pregnancy. And only now I realized that my belly is growing and becoming firm. Still, friends haven't said anything about it yet - when dressed in a sweater or something slightly thicker... The weight of the baby is normal. She gained very little herself. And I don't know what to think ?