Much more info needed! Are these autos or photos? If photos how long will you veg them? What does the genetic say the time line is?
Some autos can finish in under 60 days, while others run 130+.
A photo plant can be placed in flower at 3-5 weeks old, sure it wont get huge but a sativa may need 12+ weeks in flower to ripen.
If its indica and flipped at 3 weeks you may pull it off.