Rick’s answer to “Hello Uncle Rick! I've heard that many people start writing by trying to imitate their favorite aut…” > Likes and Comments

Terry Pratchett kind of published the equivalent to those youthful first attempts, but only after brushing up the whole point of his story to fit with his grown-up perspective. :-) I believe he originally wrote "The Carpet People" when he was 17.
Had he had that possiblity, that story would have been on a forum somewhere, for sure.