Not really , the time stamp will be made by her server not urs.
However you could send a email to the wrong place on purpose , e.g instead of:
homework@(you need an account to see links)cher.co.uk
send to:
homework@(you need an account to see links)cher.com.uk
This will give you a automated email reply back in your inbox saying the email failed , screenshot this and change the date. Now tell the teacher you made a typo when sending the email originally and only noticed today , use ur fake sshot as proof. It might work .