If you performed well in high school, you probably have aptitude in mathematics.
Although mathematics at a university mathematics department differs greatly from high school mathematics,
efforts to acquire habits and understand conventions to think theoretically until you are convinced of something will help you understand university mathematics.
To assist such challenges, the Mathematical Institute assigns graduate students as tutors or allows students to ask questions to teaching assistants about exercises.
Of course, students are welcome to visit laboratories to ask questions of lecturers.