does anyone have or know of resources suitable for middle school aged students?
I don't think that there is any C++ on it but have you looked at https://hourofcode.com/ca/learn There are some great age appropriate resources for use. I use the Ozaria python game in my grade 10 class even though it is listed at grade 6-8. Chapter 1 is free to use. As a teacher, you build a class and get to see where each student is and you can click on their assignment to see their code. It's honestly pretty slick. There are lots of free fun python games to start and the compiler is free online. That is if you are not adverse to changing from C to Python.