GCSE vs A Level History

I've recently found out that I will have to a different sixth form than I originally was going to attended.

I found out that at the new school the history course would cover Weimar and Nazi Germany for AQA. This is the same topic I did at GCSE except I did it with Edexcel.

Are the courses really similar? I worry that I'll find it rather boring.

A Level history is in much more depth than GCSE history, you will absolutely be looking at things that you didn't look at during GCSE history. Even if you knew every single piece of information in the A level textbook, you could still go further with wider reading if you wanted to. I would see this as a bonus. You have a good general and brief understanding of the time period, that will help with the transition to A level history, but still have plenty to learn about.
I think this would only be a cause for concern if you found the Weimar and Nazi unit you did at GCSE boring. Even then, I have personally found A level history to be much more interesting than GCSE history.