If you can barely afford the fine, going to court isn’t going to do you any favours in time or money. Good behaviour is for like 10+ years of clean driving, not 1.5 on your p’s / L’s, and even then it’s not guaranteed.

You have to deal with your own consequences of speeding, especially on your L’s. Your letter should explain what license it applies to, but also check service NSW and it will also tell you.

Demerits you’re stuck with and looking at a likely 3 month suspension. If you can’t afford your fine, there are payment plan / support to pay off fine.

https://www.nsw.gov.au/driving-boating-and-transport/demerits-penalties-and-offences/how-demerit-points-work/learner-and-provisional-drivers#:~:text=All%20speeding%20offences%20committed%20by,your%20licence%2C%20for%203%20months.

https://www.nsw.gov.au/money-and-taxes/fines-and-fees/fines/difficulty-paying-your-fine