Bro every school in every country in every place in the world does different things for their first semester, not every school does the exact same thing. I recommend just learning everything you can when it comes to things like maths, science, english, etc. That way you might be ahead of everyone, which is always better than being behind.
Honestly don’t worry too much. Teachers should be understanding about that and they usually do a review and you can always ask questions. Also it is just seventh grade so you have a lot of time to catch up. Good luck hope you do well!