I asked this question which, having read answers and comments, Should have been a very different question. Probably should have been flagged as opinion based =]
I've accepted the answer from Carcer as they rightly questioned my throwing someone in the deep end of 5e, but in actual fact I'm first going with a suggestion from Engineer Toast (in a comment on the question).
I was about to post an answer myself as such, in case other people stumble into the same problem - but my chosen solution (I'll try Heroes of Hesiod, and she can level-up to a lvl1 adult-5e-person once the basic mechanics are understood) isn't actually an answer to the question so my self-censor-mode kicked in.
Is this the correct way of dealing with the situation? I didn't want to change the title as it would invalidate good answers to the original question. But in hindsight it's not the question I should have asked.