Demirköz is from Istanbul. She attended Robert College for her high school studies. She wanted to take part in research during her undergraduate degree, so moved to Massachusetts Institute of Technology. She won Joel Matthew Orloff Award in 2001. She earned a Bachelor of Science in Physics and Music from Massachusetts Institute of Technology in 2001. She started working on the Alpha Magnetic Spectrometer. She was offered PhD positions in California Institute of Technology, MIT, Stanford University and Harvard University. Despite originally starting her PhD at MIT, the Space Shuttle Challenger disaster resulted in her moving to the University of Oxford. She was a Science and Technology Facilities Council Dorothy Hodgkin Scholar under the supervision of Antony Weidberg. She eventually completed her postgraduate studies at the University of Oxford, and was a member of Balliol College. Here she worked on the ATLAS experiment. When the Large Hadron Collider was delayed, Demirköz tested her detector using cosmic rays. She completed her thesis, "Construction and Performance of the ATLAS SCT Barrels and Cosmic Tests", in 2007.