A level Subject Changes

Just started Year 12 this year. It is current October 6th and I have been told I can no longer change subjects. I am doing Law, history and film studies. Not enjoying film studies at all and want to change ur to politics but am being told I cannot. Am I able to change my options at the start of year 13? Can I drop film studies course and do a A level Politics instead?

The only thing that happens in year 13 with regards to changing options for 3 A Levels is: you do badly in your year 12 mocks and year 13 mocks in November/January (As in getting E’s), the school may make you drop one of your A Levels or change an A Level to an AS Level one.
This happened in my school, a girl in my chemistry class got an E in chemistry mock in January (4 or 5months away from the summer exam), so was forced to drop it and take core maths. Core maths is equivalent to an AS Level.

It has only been a month, you chose to study film studies, there was a reason why you chose it. Im sure there will be interesting parts to it, but you have not encountered it.