its up to u really, if u really think that u will never suceed in the subject then might as well drop it now. but provided that u drop it before year 12, u should be fine (you will learn pretty much everything in year 11 standard in year 11 advanced anyway, i think the only topic u don't touch is financial but u can always learn that over the long holidays between year 11 and 12 worst comes to worst). i think u should give it a try for a bit longer though, i along with a lot of other people were quite confused at the start of year 11 because all of the terminology and language is new, but by the end of year 11 i got 98/100 in the prelims and slept through half the exam