Hundreds of schools across the state have already been occupied by students angry over government's plans to freeze education funding.
The protest has spread to other states.
Ana Julia was applauded when she criticised the government's education plans in the course of the session in the Commission for Human Rights inside the Senate.
She has been compared on-line by Brazilians for the Pakistani activist Malala Yousafzai.
In an interview together with the BBC, she said she did not know that the comparison had been made, but she liked it.
"How incredible! Malala is anything else, her campaign is fantastic."
Ana Julia gave her speech to legislators in her property state of Parana final week within the midst of student protests in about 1,000 Brazilian schools.
Parana has been most impacted by the sit-ins that started in early October and has over 800 schools occupied.
She started her address using the query - who is college for? She went on to defend the student occupations as legal and genuine.
The occupations have already been criticised for closing down college buildings made use of for annual examinations.
A conservative, right-wing organisation, the Movement at no cost Brazil (MBL), and some parents and teachers have demanded the protesters leave.
Some have argued that the secondary students are being politically manipulated by left-wing politicians to put stress on the government of President Michel Temer and on the governor of Parana.
But Ana Julia said in her speech it was an insult towards the students to say they had been indoctrinated.
She said they have been defending their education and they had a correct to protest against the government's plans to freeze education funding for 20 years.
She mentioned the students read the news meticulously and debated their response to what was getting said about education.
She argued that a controversial government programme, "schools with out political parties" which forbids political discourse inside the classroom was an insult to the capacity of students to consider for themselves.
Above all, she stated, students needs to be consulted on what sort of education they wanted.
Quite a few left-wing supporters in Brazil are deeply disillusioned with politics just after the impeachment of former President Dilma Rousseff and the discrediting of her Workers' Celebration.
This week the austerity measures aimed at freezing investment in education for the next two decades go to the Senate, following getting passed by the lower house of Congress.