Mom of 2

I am 21 weeks and expecting a baby girl. I already have a 9 year old son and he is just absolutely perfect .. so well behaved well mannered.. I never have to yell or scream at him. He’s honestly like my best little friend. Now pregnant with baby #2 and being a girl I’m just SO nervous. I think because of the change of 1 to 2 but also because idk how to be a girl mom. Anyone else experiencing happiness yet lots of nerves ?