Chemistry is not to be taken lightly. It isn't like the concepts are thrown out the window after yr11. Everything you learn in chemistry is built up from.
While I can't actively remember anything I learnt in year 11, I can say the same about every year of school so far. I don't think you'll find anyone (who isn't a dick) who says HSC chem is easy, cause it aint.
KNOW THAT CHEMISTRY IS HARD!
If your brain doesn't work along the right line you are going to have a very miserable year.
Are the reasons you ask a love for chemistry or a fear of something else?
-Pete