What she is doing is similar to implementing her own Lisp or Forth interpreter. It does not matter whether it will ever be used in production, what matters is l

What she is doing is similar to implementing her own Lisp or Forth interpreter. It does not matter whether it will ever be used in production, what matters is learning whilst building, as opposed to by wrote. You do mention that working on somebody else's construction would be useful, and would give a different perspective on the problem, but that process emphasizes different skills. Treat her wheel reinvention project as an investment in her future as a programmer and a systems designer. Re-building things that others have made to discover how they work is one of the first, vital steps in the process of developing new ideas and approaches to problems. I would also add Rust offers some really great semantics, and it's well worth the trouble to see how a kernel would look in it. It's been a while since we've had a new, reasonably well known language that is truly capable of this level of systems programming.