Ideally I want to get my plant to about 2 feet than top it. How soon can I go to 12/12 for flowering and do I use 12/12 for flowering the whole time andddd for how long do I let it flower before harvesting the fruit? So basically I want to do this quick, not for selfish reasons but I have nosy teenagers.
You can go 12/12 whenever you want to, but the longer you veg the larger your yield upon harvest.
Flowering is determined the genetics of the plant, whether its indica, sativa or ruderalis (auto) among other factors like medium, light etc.
so basically your plant will be ready for harvest whenever it is ready.
also purchase a loupe or scope to check the trichomes when harvest is near