At least you understand, and know how to approach situations without negative remarks...
Hey Sir Jonse!!
This time last year I was doing something really similar to you! Basically I wanted to go really ahead (like yourself), in subjects like chemistry and health. What I did different was that during this holidays, instead of doing really difficult questions like you are, I spent it just going through the theory, making summary notes and making sure I understand all the content.
This way, I wouldn't have to waste much time after February, when school starts, making summary notes and stuff. Because making notes/reading the textbook/doing textbook questions is actually not that valuable as doing exam questions. So I found it very useful going through this on the holidays.
I think you should probably try out that approach. Make you summary notes/go through the content, and then save all those tricky questions when you begin year 12 and will have a teacher that can aid you.
Good luck!! Really good to see that you're using you holiday time studying!!