When Mitchell Sayer first looked at the English HSC paper he thought he "was going to throw up", but the nerves disappeared once he started writing.
"The first 10 minutes, reading the whole paper was very stressful," said Mitchell, 17, who is in year 12 at Kogarah High School in Sydney's south.
"But then it started to align and I became a bit more relaxed."
More than 60,000 students across the state sat compulsory English exams on Monday, marking the start of the HSC exams.
Mitchell said the two-hour exam was the one he was dreading the most because English is his "weakest subject", and he thought the "unseen texts" section of the paper was the hardest.
"You've been exposed to [none of it] when you've studied and you need to write so much," Mitchell said.
He will also be sitting the maths, Japanese, visual arts and business studies exams over the next three weeks, but said he planned to take a little bit of time off to celebrate his 18th birthday on Sunday.
"I'll go out for lunch, but then I have to come back and study for maths, which is the next day," Mitchell said.
"I'll probably celebrate properly in November."
Shaun Guo, 18, who is an international student from China and also doing his HSC at Kogarah High, sat the English as a Second Language exam on Monday morning.
"I was nervous at first but it was OK," Shaun said.
"It's not hard but it's also not easy because it's the HSC. English is harder [in Australia] but some subjects like maths and chemistry are harder in China."
Shaun moved to Sydney at the beginning of year 11 so that he could do the HSC, and said he is aiming for an ATAR of 75.
"I want to study teaching at UNSW; I'm interested in [teaching] high school maths."
Shaun will also sit the chemistry, maths extension 1, Japanese beginners, and Chinese continuers exams.
A total of 77,975 students are currently studying at least one HSC course and 70,270 are expected to complete their HSC this year.
This year's exams include a total of 117 written papers and will finish on November 7.
Deputy principal at Kogarah High, Vanessa Williams, said students were always the "most anxious in the lead up" to the exams.
"The tension eases a bit once the first exam is over; I saw lots of smiles [after the exam] today," Ms Williams said.
She said teachers get very nervous about the HSC, too.
"The teachers are there when students come out of the exam and they're just as keen to get the paper, they agonise over questions and quiz the students about how they found it," Ms Williams said.
"There's always lots of pressure put on the HSC as a teacher; you try to refine the advice you give [students] and remind them that there's a bigger picture and not to get too wrapped up in exams."
She said her top tip for students doing the exams was to "eat breakfast".
"And make sure you're studying hard but also balance that with rest breaks and time outside."
Ms Williams said she still remembered doing the exams herself.
"I had an exam every day for six days, it was over like that," she said.
This year marks the 50th anniversary of the exams and more than 2.3 million students have done the HSC since it began, Education Minister Rob Stokes said.