I think Vash was just giving fair warning...
A friend of mine, a postdoc at the time, had her second child. When I asked how it was going, I commiserated by making a comment about how I heard that having two was actually easier. She looked at me directly and said "Whoever told you two is easier LIED, mbe to share the misery (lol). Its not, especially when they are both preschool age." They were just over 2 years apart, btw.
From what I've seen, it got easier once they were older. It helped they were the same sex, so played (and fought) with each other. Having a boy-girl, is like having 2 separate kids from what I've seen.
Anyway, its good you are thinking about it and preparing. Much better than not thinking about it at all. Hang in there with the job, you will appreciate having done so later.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh