Gongrats on your future arrival. You'll find doing the ATPL licence very similair to being a dad - you throw money at something, it does not thank you for it and screams at you all the time - that's just the flying school!
Seriously though PPL exams are a lot less work than ATPLs, so I would advise you if you are intent on the modular route to do your PPL first and enjoy flying a bit (you'll need 150 hours anyway before you start the CPL/IR course). It will also reduce the risk for you as you'll get a flavour of what is involved and whether you do enjoy it.
I think if you were considering an integrated course, however, the advice would be the opposite - just do it asap! BUT research it FULLY FIRST.