I started using DOS to run games at around 4, when my dad bought a PC, and taught myself batch programming and QBASIC when I was 6, so I think the ages you mentioned are probably correct.

(For many months, I had no idea there is such a thing as "else", so I used to end the body of "if" statements with a "goto" to jump over the next few statements to emulate the effect of an else clause.)