Can you pick up a brand new subject in Year 13 sixth form for A2?

Currently I'm taking Maths, Product Design and History for A levels in year 12. Next year my mum is planning on moving me to a new school for year 13 as it's closer. I'll be carrying Maths and Product Design over however for history they do not share the same exam board as my previous school. My current school is OCR, my presumable new one is AQA.

I've heard switching to a new exam board for subject like History(or almost any) is basically choosing a new subject as it's got completely different course material. However I'm not sure if they're going to start anew with Year 13 history and their course material. I was thinking of switching that to Classical Civilization which is the same exam board(OCR) and also it does have my interest as well! I easily pass the entry requirements for either and I think switching to Classical Civ would essentially be the same as joining a new history exam board.

They are both also essay subjects. Although I'm not too sure and need other opinions and reassurance to know if what I said is right or not. Thanks!