You can not select a future date to file your return. You just need to wait to file it then. Did you go to the very end, through the File tab, through the 3 steps and hit the big orange Transmit Returns Now button? That's the only way to actually file. And it actually says Transmit Returns Now.
Do you have a tax due? That might have been to select when to have the IRS take the tax due out of your bank account.
