The age you are now is the best time to start.
I'm working with my 8 year old granddaughters on Creative Writing. Hey that's not Data Literacy? Yeah it is. In order to write you have to write a million questions first. Where is the Narwhal family going to live? Do they have any relatives in the town? What will daddy Narwhals job be?
Curiosity is a critical key to Data Literacy. Gotta learn to ask questions, more questions and then another question.
Point of my rambling is that Data Literacy is all around us if we tie the elements together. We don't have to say "Hey let me teach about data." Let's Montessori this stuff. Teach it where there interests already lay and work from there.