Same way to write self referential structs - use index types into the whatever arena you are using. Indexes are usually 32 bit so they are a bit faster than pointers.
If you are building one off trees such as for parsing and ast transforms, bumpalo is your friend.
In your case, you can look into generational arenas and slabs which are useful for graphs.
Don’t dim screen on iPhone during conversation.
The tutor should terminate the lesson when its goals are achieved and do a warm handoff.
Overall it’s quite good.