Your application with the IRS should actually be more simple because of your experience rather than less.
Remember, most applicants are in the exact same boat as you (brand new) without the benefit of experience. The IRS expects you to give best-guess estimates, and you have the advantage of better best guesses. Your guesses on annual fundraising take and annual expenses will be pretty good.
The IRS isn't out to get you on this, and after a few years your actual numbers will be far more important than your guesses. IRS is just trying to get a feel for what you'll be all about.