I think any time you're comfortable having it is fine. There's nothing wrong with planning :)
I'm due June 20th and wanted an April shower but everyone I know has birthdays in April, so picking a w/end was hard. I have my shower booked for May 5th.
I think any time is good give your self plenty of time to organize and also get last minute things before the baby comes.
No am due june 2 and ama do mine on march to have time to buy everything nd not bee in stores getting tired really fast cuz ama be more big