I'd recomend doing what you enjoy. If ur enjoying chem, stick with it, but make sure ur gonna keep enjoying it. Think of what's enjoyable about it now and try keep that attitude going. If, however, you decide to go to senior science, make sure u enjoy that too, keep up with the coursework and such.
No point doing a subject you don't enjoy
Oh, and with teachers, i had a grand ol' chem teacher. We <3'd her muchly. Physics teacher was also great. She brought us food; knew how to keep us students happy.
Same here with wrxsti, I got low 70s to 80s in my assessment tasks and exams but then were much higher in the HSC course.
Senior Science might be really exciting at the start and you may lead yourself to believe 'i'm going to ace this, it's so easy!', but then further down the year when you have finished the course it might be difficult to study for it since you've covered everything and it may not really be a challenge, especially during the Trials period and STU-VAC (Well that's what happened to me for Biology, it was so repetetive).
That's just one viewpoint.
Chemistry is a subject which has various challenges throughout since there are hard topics which require some calculating manipulations and problem solving and some content is also a bit hard to grasp. It's also one of those subjects which teaches you about modern technological advances like Biodegradable products, Climate Change, Ozone Depletion, renewable energy such as Ethanol - in fact it touches on the environment quite a lot (what the ecological problems are and ways to solve them). This might keep you going to try even harder in it and remain focused on this subject since it affects our lives now and in the future (well it did for me).