Do I need S-Corp Acceptance Letter (CP261) before filing corporate 1040?

I started a company though BizFilings in late 2019.  The relevant dates are: 

- IL SOS Acceptance 11/26/19

- Federal EIN received 12/2/19

- Form 2553 sent to IRS 12/2/19

 

According to the BizFilings rep, S-Corp acceptance letters (CP261?) are taking like 90+ days.  I did my first-run of my personal taxes with estimates, and 2019 is going to be a big refund for me.  My books are pretty easy for the (unapproved) S-Corp, but I can't file my personal 1040 until I have the K-1 from the company.  Other than the obvious what-if-the-IRS-rejects-your-2553 risk, can I transmit my corporate 1040 and print my K-1 before I receive back the approval via a CP261?  The business is starting to lift off the ground, and my personal refund would give me a much needed injection of capital.

 

I am the only shareholder.