The First Minister was reopening a debate at Holyrood over her calls for a second independence referendum.
“Scotland, like the rest of the UK, stands at a crossroads,” she told MSPs.
“When Article 50 of the Lisbon Treaty is triggered tomorrow, change for our country at that point becomes inevitable.”
She added: “It is change that will impact on our economy, not just in the here and now but in the long-term.
“There will be an impact on trade, on investment and on living standards, and an impact on the very nature of the society we live in.”
She continued: “My argument is simply this: when the nature of the change that is made inevitable by Brexit becomes clear, that change should not be imposed upon us, we should have the right to decide the nature of that change.
“The people of Scotland should have the right to choose between Brexit - possibly a very hard Brexit - or becoming an independent country, able to chart our own course and create a true partnership of equals across these islands.”
Ms Sturgeon is asking for Holyrood’s backing to call the power to stage another vote between autumn next year and spring 2019.
The two-day debate on the issue started last week but was suspended as news of the terror attack at Westminster emerged.
MSPs will be asked to mandate the Scottish Government to take forward discussions with the UK Government on the details of a section 30 order, the mechanism to transfer the legal powers for a vote.
The Scottish Greens are expected to give the minority SNP government the support needed for the motion to be passed as the other parties have indicated they will vote against it.
Ms Sturgeon met Theresa May in Glasgow on Monday and the Prime Minister has said ‘’now is not the time’’ for another vote, indicating she will reject the SNP’s preferred timetable.
Following their discussions, the First Minister insisted the Prime Minister had been clear the terms of the UK’s divorce from the EU and the details of a new free trade deal would be known within two years.
“I think it makes it very difficult for the Prime Minister to maintain a rational opposition to a referendum in the timescale I have set out,” Ms Sturgeon said.
Liberal Democrat MSP Alex Cole-Hamilton said: “We utterly reject the false dilemma this government and the Green Party seek to create in casting this as an unambiguous choice between two unions.”
He added: “Such is the division on this issue of the nationalist base this government is trying to ride both horses, but I say to them remain voters will find you out and we shall not be the unwitting fulcrum over which you tip this nation back into the divisions of the past.
“The 2014 referendum caused such friction in our society, one in four report a damaged relationship with a friend or family member as a result of it.
“I would not see Scotland return to such a state of acrimony.