If you learned to read at age four, you did not learn to read through any sight reading program used in public schools since you were not in school yet.
Since memory from that early age is quite spotty, how do you know how you were taught to read?
Because
1. My memory from that time is crystal clear. I recall seeing words on a billboard and reading them.
2. After that, my grandmother, who lived with us then, taught me from old books, starting with prayers.