Hey hope u r well! Read down at the bottom for summary.
Good on you for taking some initiative, I did this in year 7 and 8 and was pretty much bored senseless for the next two years lol. Specialist math is an interesting topic, it is technically a uni math course which has been adapted for vce. It was built for students to take with/after methods. As a result it is most certainly harder than methods and introduces ALOT of new concepts such as vectors, mechanics, some of the algebra like partial fractions, some of the geometry, further trig, proofing and
sequences and series stuff as well is fun and new. Complex numbers are a huge part and very interesting. For the 1/2 they cover some thrilling and new graphing techniques involves matrices, complex number, locus, polar forms and more. However sorry to say that calculous does not really come up in the 1/2 :/ lucky for you the 3/4 is calculous galore. If you found the methods 1/2 and maybe 3/4 calculous easy maybe take a peak at the spec 3/4 text book if you are determined to only do calc.
The 1/2 and 3/4 text books are VERY different for spec, you could honestly do maybe 6 chapters worth of exercises from the 1/2 to go into the 3/4 prepared (assuming u done methods 1/2 or 3/4). However a big question is how sure are you about the methods? Many intelligent and sometimes arrogant people will skip through the easy skill building questions and end up missing methods and skills that show up on tests and throw them. Remember that no matter how intelligent you are, if you were smart enough to be proficient at all this stuff without having to do any practice you would prob be in uni at this point or something. It sucks and can be boring but sometimes just buckling down and doing the hard stuff is the only way to learn. But ur in year 10 so will cover all those exercises in more detail next year, as a result if you are already confident with the concepts then I would recommend doing the methods 3/4 exercises and doing some of the 1/2 homework as revision if you are SUPER confident.
TLDR: Spec 1/2 is fun, but the 3/4 has more calculous if u r committed. Methods 3/4 is a big extension of 1/2 and is important to know. Remember that passion and motivation is more important than trying to get a high score in subjects ya hate.