Wong and other pro-democracy supporters say the case is more proof that Beijing is tightening its grip on semi-autonomous Hong Kong.
But the student activist said he felt "guilty and sorry" for what he described as the burden he has put upon his family, a day ahead of a court ruling that could see him and two other prominent young activists jailed.
Wong and other pro-democracy supporters say the case is more proof that Beijing is tightening its grip on semi-autonomous Hong Kong, which enjoys much greater freedoms than on the mainland.
Those rights are guaranteed in the agreement made when Britain handed Hong Kong back to China in 1997, but there are growing concerns Beijing is trampling the deal.
"I expect to pay the price, to be sent to prison," university student Wong, 20, told AFP.
"However, I have no regret at all. What we have done already proves that Hong Kong people will continue to show determination in the frontline against authoritarian rule."
Umbrella Movement leaders Wong, Nathan Law and Alex Chow were found guilty last year on unlawful assembly charges for storming a government forecourt as part of an anti-Beijing protest in 2014.
That protest sparked the months-long rallies which brought parts of Hong Kong to a standstill calling for fully free leadership elections, an unprecedented rebuke to Beijing.
Wong and Law received community sentences and Chow a three-week suspended sentence at magistrates' court last August.
But Hong Kong's justice department is seeking to overturn those terms, with prosecutors arguing they should receive harsher punishment.
Inciting or taking part in unlawful assembly carries a maximum sentence of five years.
Chow, 26, said he was not scared.
"When we are willing to sacrifice what we have, there is nothing to fear," he told AFP.
While Wong also says he is mentally prepared, he worries about what he has put his loved ones through.
"I feel guilty and sorry towards my family," he told AFP.
"They have brought me up and spent a lot of money, letting me take part in social movements but only to be sent to prison in the end. I said I would keep up my studies in prison," he said.
There have been a raft of cases brought against participants in the largely peaceful Umbrella Movement, but only one prominent activist has ever been jailed.
The High Court judge at Thursday's sentencing review hearing can deliver an immediately effective prison term.
The defendants say they are pessimistic after 13 environmental activists saw their community service sentences over demonstrations outside parliament upped to jail terms earlier this week following a request from the department of justice.
Wong says if the judge in his case hands down a harsher penalty Thursday, it would make it harder for young activists to enter politics.
He will turn 21 in October and has said publicly he intends to run for parliament.
However, if he is jailed for more than three months Thursday he will be barred from elections for the next five years.
"We are fighting for justice, not for personal interests," he added.
"I will continue with the spirit of the Umbrella Movement to fight for democracy, even if tomorrow I am in jail."