Bismihi-Taala. As-Salamu aleykum I grew up in a muslim family. But my father and mother have been very ignorant, and both they haven't know the Islamic religion and they couldn't teach us this religion. Instead, they sometimes they negate the afterlife (Ahkirat). Such that they say "is there anyone who came from another world (underworld)". I started praying at my seventeenth. However, I was not grown up mentally (thinking) even though I was grown up biologically. Such that I did not understand the purpose of the creation. However I lived just biologically, and Idid not understand this kind of things at all. I knew that there are praying, fasting, but I did not undertsand totally, I even do not remember thinking about it. So that I have been so much ignorant. I lived a secularistic life. Even after starting praying, my parents also have been against my living a religious life. In that case, is it necessary for me to re-do (qadha) the prayers and fastings that I did not perform before age seventeen?