How long should i wait to test

This is my first month using glow, i previously didnt track my periods as i knew roughly when it was due and wasnt TTC. 
​I was sure i had a 28 day cycle. We have only been trying for 2 mnths now and im now on cycle day 33. 
​Im to scared to test because i dont want that BFN. How much longer should i wait for AF to come before finally having the courage to test?