Well, that is how the Schedule C on the 1040 works - it asks if your business started in 2017, and eventually it asks the question of when you started the trade or business...however, that is surely a different software code base, so that may or may not be how they designed the 1120 interview.
However, I note that it asks you this question (did your business start in 2017) only once...once you have set up the initial business info, it never shows it again. I had to "Add a(nother) Business" to get this question to appear.
I don't know how far along you are in the data entry; would it be reasonable to clear and start over or have you entered too much into the system?
