That sounds eerily like myself. I was also shy as a kid.
Honestly, I find most introverts to be the most talkative believe it or not. Once they trust you and have your full attention, they can go on for very long stretches without a single break, all while I'm slowly dying inside. I'm way too aware of "my public" and my surroundings for that. I'm too succinct.
I can be very animated and love to speak at times, but I always want it to be a lively conversation where everybody is just throwing words into the ring - not just me. And certainly not one at a time.