I'd favor video lectures. What you're proposing is pretty ambitious for teen learners, so (posted) videos will allow them to rewatch them, pause to take notes, etc. Good luck!
I tend to favor video as well. My kid is almost through with MIT 6.00.1x Intro to Computer Science with Python and he's done pretty well. I've helped him along the way but was happy to see him need less help as he progressed through the course.
Part of me thinks that starting at a much lower level might actually be easier in some ways. Not sure at this point.
Part of me thinks that starting at a much lower level might actually be easier in some ways. Not sure at this point.