One guy who was about 24/25. He came in already experienced in creating extensions for clang and LLVM. He wanted to do a masters in cyber security. I told him to get a job, but we became friends instead.
When I wrote my first if-statement for an operating system course, he finished the entire program. It was unreal to see. Funnily enough I was quick enough to read his code and to see where he'd be sub-optimal in his architecture.