The New York Times has a forum discussing when children should be taught programming.

http://www.nytimes.com/roomfordebate/2014/05/12/teaching-code-in-the-classroom
Computing in the Classroom
MAY 13, 2014

following up on the article

http://www.nytimes.com/2014/05/11/us/reading-writing-arithmetic-and-lately-coding.html
Reading, Writing, Arithmetic, and Lately, Coding
By MATT RICHTEL
MAY 10, 2014

Jonah Sinick did the service of collecting previous forum threads on programming at

http://giftedissues.davidsongifted....5425/Davidson_forum_threads_on_prog.html
Davidson forum threads on programming resources

I am neutral about teaching programming in elementary school. There are more basic and important things to learn. But students in middle school who have the ability to learn algebra and other abstractions may also be ready to learn programming. Several algebra textbooks have computer programming exercises presented in BASIC, which is no longer pre-installed on IBM PCs, although many versions of BASIC can be downloaded. I think supplementing algebra with exercises in a modern language like Python is a good idea.

Your age is showing. There's almost no such thing anymore as an IBM PC.

DD9 was invited to join her school's robotics team, which is basically a programming course. They are given the robot, and they program it to perform real-world tasks, or "missions."

I couldn't possibly come up with a better way to introduce kids to programming. It's competitive, it's goal-oriented, and it relates programming to real-world problem solving.

It depends on what the conceptual reason for teaching programming is. If the reason is to teach a technical skill, then sometime after Algebra1 makes sense. If the purpose is to demystify technology, then soon after that big abstract reasoning leap isn't a bad idea (NT ~10.) If the intent is to teach executive function skills, organizing thoughts, planning, problem analysis and deconstruction, then the sooner the better.

To the more metacognitive intent, then programming adds to skillsets developed through organized play, games, regular instruction, and other structured life events. What it offers is a microcosm of planning with a strange juxtaposition of delayed gratification (have to plan first and carry out the steps) and immediate feedback (did it work.)

It may in some ways be a better bridge into executive function for kids in household situations that aren't getting those sort of scenarios with real tangible personal rewards. A classroom gold star or theoretical admittance to a college in 10 years is just not the same as successfully programming your little dude to turn a cirlce and shoot his laser while yelling "Banzai".