Hey there, great grow ! first let me just say you're the first person on the site to complain about "too quick" for flowering lol. but to answer your question it's a genetics issue : some phenotypes are quicker than others and some strains are quicker than others, so i guess you have a quick strain with a quick pheno, so after 8 weeks of flower it's ready to come down. it's not uncommon to find some quick flowering genetics. It's not your fault ! I hope this helps ! 🚀