Definitely
It's only one task. You'll get better as you go through the year. Focus on learning from these mistakes so that by half-yearly exams and trials, you don't make the same mistakes. Trial exams are usually the hardest and will separate the most people. Make sure that you study to get the best mark on trials since it's also worth the most for your internal exams.
I know it feels hard to envision it now, but you can definitely get better over the year. If you learn from your mistakes and put in the work, you could easily get above average. Remember that E4 (Equivalent to a band 6) in Ext II is only about a 70/100. You are only 12% off. Since you go to a top 20 school I'd assume that your exam was harder than HSC, so this gap isn't really 12% and could be much smaller.
