I'm going to share a statistic that, although it sounds like I'm bullshitting, is 100% true and you can fact check me on it.
In the last 5-6 years (as far back as I think it sensible to check), no one who does Standard English has
ever achieved a 99.95. There has always been 99's, often around 99.50, even up to about 99.75 or so, but never 99.95.
You
can still achieve a 99.95 ATAR, but your odds are
significantly reduced in terms of being able to crack that score. Even if that isn't your aim, you are significantly disadvantaged by the scaling of Standard, for a course with a completely equivalent workload to Advanced.
Students should pick subjects that suit their skill level, of course, but anyone who does well in Standard can perform to a similar level in Advanced. In honesty, I'd be going to your teacher and demanding to be moved up. It is your HSC, and you've not given them any reason to stop you!!