That's pretty good if that's your first email like this! Your teacher would definitely understand you.
Generally in a formal email, there's a set structure we go by. We first put the name of the recipient, followed by a greeting, which you have done. We would then generally say who the email is from. Something like:
Make sure to replace the ○○s with your teacher's name, what class you are, and your name.
For the body of the email, we generally start out by first saying what the email is about, followed by your request. Introducing the main topic of the email is generally accomplished using「〜(について/の件)ですが、」 in some form or other. This is then connected to the rest of your email body. Also, here,予約 is not necessarily wrong, but it sounds a bit impersonal. It may be better to ask if your 先生のご都合がいい (if they're available) on the 7th. Which happens to be tomorrow. So something like:
About the homework check,
Tomorrow, is there a time range you're available?
Then we might finish up by apologizing for disturbing your 先生 with this email, and finally end with よろしくお願いいたします.
In total (assuming your teacher knows about the check you reference):