Of course there has been a time when I did not yet know how to read, but I can't remember it very well.
To re-evoke the feeling of not being able to read is not so hard, though; I simply have to look at anything written in Cyrillic characters, Arabic writing, Chinese signs and so on to remember what it was like before I was five years old and my sister taught me how to read after she had just mastered that art during her first few weeks at school.
The letters that are used in the precious few languages that I do know are very common all over the world, and so I can often "read" something even if I do not understand it.
And although I know exactly that I haven't got a clue about Czech or Hungarian (these two just being examples for the vast majority of languages that I do not know), I am still compelled to read whatever crosses my path.
Whether I am interested or not.
I read, because I know how to.
I read, because something written is there, in front of my eyes.
I read, because the letters do have a meaning and were put there, and in that order, for a reason.
I read, because I can't help it.
The milk carton, the adverts on the train, the cryptic error message on an internet page that does not work properly, the times on a sign that tells you when you are allowed to park at a certain spot in town (I do not even own a car)... all these, and much much more, I read. All the time. There is no stopping it, no un-learning of something as basic as this once I had learnt it.
And so I keep reading.