Although I didn't start to take music seriously until my dad brought a bass home, I started taking guitar lessons from him at age 8. He was a professional musician and educator, so I had about 3 years of private lessons- reading treble clef, learning about rhythm, scales, chord structure, etc., before I switched to bass at age 11.
I did my first recording session at age 12. My dad got hired to record a bunch of short cues for a multi-media presentation that Kodak was exhibiting at Expo '67, in Montreal. Don't get the wrong idea, I was far from precocious. My dad taught me some simple blues progressions, but I muffed them repeatedly. We had to start over each time (remember, this was home recording in 1966, so there was no multi-tracking, just a single mic in the center of the room, connected to a reel-to-reel tape deck). As a result, a few minutes of music took about an hour to record.
In order to get me more motivated, he had promised me a full share from the proceeds, which came to $225.00. Needless to say his plan worked, and I practiced a lot harder after that session. Sadly, $225 per hour remains my career high, 45 years later!
My next gig was for a Grade 6 prom (we were all in Grade 8!). $15 for three hours. We had to pay the drummer's mom $5 for gas, so after expenses, we netted about $3 each. We had no PA, so no-one could hear the lyrics, and we had to repeat our short song list quite a few times, in order to pad it out to the alloted time. Quite a comedown after the recording session...
By the two year point, I was 14, and jamming with buddies in a couple of pickup bands. Good fun, but there were no further paid gigs until two years later, when my dad got me a Union card, and started taking me out on casuals, mostly weddings and banquets.