Baby #2 need advice

Okay I have my 2 year old son now I’m about to have baby # 2 and she a girl I mean he went with me to my ultrasound appointment yesterday and was like baby sister is in the water 😂😂 but at the same time I don’t think he fully understands on that baby sister is coming soon but I’m hoping that I’m doing enough to prepare him for what’s coming just worried that I’m not...