It really depends. I personally find it quite enjoyable, and in fact really not that hard. It's a language subject, meaning it's half logical, and half art.
I had next to no knowledge of French at the start of this year, but now (the end of year 11), I've gained substantial knowledge of the language.
If you want to do well, you should --REVISE REGULARLY, because it's all entirely new knowledge for you, and you build new knowledge on top of old knowledge, if that makes ANY SENSE.
--DONT MISS MUCH CLASS and if you do make sure you catch up properly or you may fall behind easier than in other subjects, as French exams are harder to bullshit.
-- BE AWARE THAT THERE ARE LISTENING, SPEAKING, READING, AND WRITING ASSESSMENTS - so you should be focussing on building your ability to understand spoken and written French, and your ability to write and speak in French.
--HAVE FUN. It really isn't too hard, and you're not expected to be amazingly fluent by the end of year twelve - although you pick up the language expenentially. Don't be scared. It's a good subject, and a good break from conventional Maths/Science/English subjects.
Hope you pick it - my entire school year has less than twenty people and the number is falling