Lexi was 7 at the time so she came to the hospital with us.
Since Kayla is younger, I dont know how she would handle it. It may wind up being more stressful. What if shes bored, what if she gets upset, etc. You dont need any added stress while delivering.
I would probably leave her with family, but made sure she was there right before the baby is to be born this way she can come in right after hes born so she can still be the first to meet him.