No, it is not late if this is your situation:
If you efiled before the deadline, did not request an extension, and your return was rejected, if you owe taxes due, you have a grace period of 5 days until April 20 to either correct things, resubmit, and successfully efile, or to print, sign, mail, and postmark the mailing on or before April 20.
If you are due a Federal refund, timing is not as critical as explained in this FAQ:
FAQ:
What if I e-filed before April 15, but my return got rejected after the deadline?
https://ttlc.intuit.com/replies/4193187
