Quick question for experienced outdoor or indoor growers

Hey guys im a fairly new grower and my question is if i let my seedling grow to a certain height in natural sunlight durring its veg stage can i take it out of that environment and bring it inside under a cfl or led and force it into flowering or would the sudden change in light harm my lovely ladies? Also i heard just putting a trashcan or box around your plant for 12h could fake your plant into thinking it is dark but id just like to get it big and bring it inside if thats possible? Any advice guys?

If all you have are CFL's, I wouldnt. A large plant needs more light.
If you had some 1000 watt hps, then yes it is possible. But the likelihood of bringing in mites or other pests would be more then I would want to risk.

Check throughly for pests before bringing them indoors.

How about a 250 watt lamp , it gets pretty hot but I think I could keep it pretty far away from my plants to prevent any burns

The less watts, the closer you'll want it, cause it will be brighter. Improve your ventilation.