good, good; I'd go for an Encrypted folder myself.
I recommend Backing the important stuff up as well; in the unlikely event that something happens to your user profile in the meantime (without the profile, you would never be able to access the files again, and we wouldn't want that)
forgive me if you already know how to make an encrypted folder, I'm just adding these steps to save time for if you don't
make a folder, and move all the stuff you don't want Mr. Nosey to see (lol) into it.
Right Click the folder, and under "attributes" click the "advanced..." button.
select "encrypt Folder to secure data".
Press OK.
this part can take a while, depending on the size and number of files you have.
Once completed, the folder should show up in green from within windows explorer.
Now, since you don't want them to accidentally or purposely access the files, you'll need to make a new profile with which your teacher can perform the necessary stuff they need to do.
Also, if you don't have one already, put a password on your account (the one you used to encrypt the files).
Now the files are only accessible when logged on under that profile.
They can still be deleted, though, which is half the reason I suggested a back-up.