Is ITIN required before Filing Due Date ?

I want to file Federal and State tax returns for 2017 as "married filing jointly" with my non-resident spouse. If I start the filing process and get the Federal Tax Return copy, I can visit IRS office along with W7 to apply ITIN for my spouse.....but getting appointment date from IRS past tax filing due date.....am I still eligible to file tax returns for 2017 as "married file jointly"? What are my good options?

Tax consultancies say that I can go ahead with Federal tax return copy and they would start State Filing once I have the ITIN for my spouse.