I am a student and my school have the older version of adobe on their computers, so when I take them home to work on my all my adobe programs won't open the files I started at school. Can I get them to work? and if so how?
There's no reason 2018 can't open 2017 files as far as the app itself is concerned. Have you checked on the file properties in Finder/Explorer to see that their permissions (read/write) aren't getting locked on your school computer? If they are set so you have permission to read/write, then there's some other problem with your installation or computer setup, and you'll have to include more details about your OS and computer.
If you're getting any messages from PS when you do try to open them, it would help to know exactly what they say, as well.