I e-filed TODAY (Apr. 15, 2019), but, immediately today I realized a charitable deduction mistake and I now owe $35 more. How do I avoid penalties/interest?

When I realized my mistake (I placed a charitable deduction twice in TT), I immediately wanted to pay the extra $35 more I owed Federal so that I don't have to pay interest and or a penalty.  Because I e-filed, I have to now wait to amend my returns.  My question is, will I be paying a penalty and interest on the owed $35  (on top of the already $2335 I paid via credit card while e-filing today 4-15-19)?  When exactly does the IRS began charging daily interest? Does it begin April 16th, even though they haven't yet processed my e-file?