How quickly can one file their tax return for the present year after completing and filing their tax return from the previous year?

[crosslife5]

I am helping my mother with her taxes this year.  About 2 weeks ago, she filed through mail her tax return for 2015. 

 I have now completed her 2016 tax return and was wondering whether I needed to wait for the IRS to process 2015 before sending 2016.  And if so, how can I know when they have processed 2015?

[fanfare · Accepted solution]

You don't have to wait.

That 2015 tax return may not be processed by April 15th anyway, so there is no point to wait.

[crosslife5]

Thank you.