well starting from seed solely and not taking cuts/ re running stuff will add some time...
i used to recall you didnt have to even wait for them to root, you could just toss em in 12/12.
or put a bag over a branch, and take a look in 10 days.
or you could just veg em out and wait for pre flowers, thats usually an indicator that they are mature enough anyways....
ultimately - time is of the essence, but patience is even more of a nail biter here. if your keen to even see the sex for 2 weeks, lol i remember my days where i'd be like that, then i'd chop in like week 7 cause they looked "good enough" lololol i was so dumb hahaha.
patience is where its at man. but throw a cut in 12/12 without it rooting, that should save some time. it should live long enough to show, but i'd take 2 just in case.