It all depends on the grower.I have put plants into flowering stage when they were only in veg for 8 weeks and they were mature.So 14 weeks is more than enough time to have them in veg.Remember that they will still grow when in flowering so if height is a problem I wouldnt let them get to big before you flower.As for the whole time of cultivation from seed to bud...that is all on the grower.Depends on how long you keep it in veg and then flowering stage usually lasts 8-10 weeks depending on the strain sometimes a bit longer....good luck