Hey jkfleur!
I can't advise you on whether your topic is okay or not because I didn't do Chinese sorry. But, maybe consider:
-whether you are willing to put in time/effort to re-research everything again for the new topic
-whether you are able to research/translate on your own or how much of the teacher's help you need
-how interested you are in your current topic vs potential new topic
-how much info you have gathered last year and how much more you need for current topic
(This might be irrelevant, but for Japanese we start our detailed study research in yr 12 anyway, so it would be possible to start this year I think, but if you need to rely on teacher/language assistant to catch up to your classmates it might be more difficult). Also if you are bored/uninterested in your topic, it'll harder to find motivation to study it. But it might be easier for yourself if you don't have to start from scratch again.
Good luck with it!!