How is it having 3 kids?

Ok. I'm really nervous now. I'm about to bring a new baby in the world and it's silly but this will be my 3rd baby and I'm mainly nervous about the BALANCE of caring for my kids. Me and my husband were discussing routines and adding another. We have a 5 yr old daughter, a son who is 15, and we will bringing in our new baby boy June 3rd. So our questions are:

How do you balance 3 kids?

Do the kids behavior change?

Is there anything new or tips with a 3rd child that we should be helpful?