No quick answer. Use a large pot so you get a large plant. If a plant has more room to grow it will take longer to veg. Top/FIM her early to keep the height down. Note: you can FIM side branches as well as main colas. Side FIM'ing will add more branches as potential clones.
All plants will start to flower even if left at 24/0 or 20/4 forever. Once your mom has started to flower move her to 12/12. During harvest keep a double-handful of greenery growing around the base of the plant. Instant re-grow! After harvest put her back to veg and do it all over again.
Good luck, BigSteve.