Grizz was correct, plants, and other growing things like trees and bushes, try to maintain a close to 50/50 amount of area between their above soil growth and their below soil growth. Of course it looks very different but in area size a 50/50 balance is sought by plants.
I have not transplanted pot plants in maybe two decades because I always use larger pots and I always start out my seeds or seedlings right in the large pot they will spend their entire life in. When I did start with smaller pots and upsize I did not like to repot during flower. There is always the chance of shock but then another thing that needs to be dealt with is normally by the time a plant is into flower unless someone is growing dwarfs they could end up with a fairly large plant on their hands and that always increases the risk of damage while repotting.
In the future when you pick pots make the best attempt you can to think like a female and if you can do that you will remember that bigger is always better and then maybe you will use large enough pots in the future. I never use anything less than 5-gallon pots and often use 7-gallon pots, and used 15-gallon and much larger when I grew outside on my deck. I think I could drop to about a 4-gallon for some strains I like and not really give much up but that is as small as I would ever consider going.
I wrote something up a while back about repotting for those who have never done it or done little of it. Maybe you know it all and more but maybe something will be of help … and if not to you maybe it will be of help to someone else.
Good luck.
For future reference .. when you repot follow the following steps.
 
Select the pot size you will be transplanting into. (I suggest growing in nothing smaller than 5-gallon pots and I normally use 7-gallon pots and I start out my plants in them and never repot.)
 
Allow the soil in the pot your plant is in to dry out and slightly pull away from the sides of the pot.
 
(The following applies if you are right handed. If not reverse the hand position/use instructions)
 
Partially fill your new larger pot with quality soil so when you insert your plant into the new pot and fill in around the rootball the top of the soil will be at the correct level.
 
Pick up your old pot with your left hand.
 
Place your right hand on top of the soil with the main stem between your first and second fingers.
 
Gently tap the edge of the pot on a countertop or a workbench or something similar. The entire rootball should slide out in one piece, possibly with a slight amount of soil loss, but no damage to or loss of roots unless the plant was so root-bound that the roots had grown through the drain holes. If that is the case if a plastic pot split the pot so they can slide through or clip them first. If a ceramic pot someone might not want to destroy it so clipping might be their first choice, though saving the roots is always better if possible.
 
You plant and rootball are then securely held in your right hand. Inspect the rootball and if it is tightly packed/twisted/root-bound slightly score/cut the edges of the rootball and also slightly score/cut the bottom of the rootball. If you do not score the rootsball the roots will want to continue to follow their circling pattern and their growth progression both down and to the sides into the fresh deeper soil will be much slower. Each cut root will push out new roots and they will go both out and down into the new soil.
 
Place the plant into the new pot.
 
If the surface level of the old rootball is to low or two high remove some soil or add additional soil.
 
Next fill in around the edges between the rootball and the sides of the larger pot.
 
Water thoroughly to cause the soil to settle without compressing it too much by packing it down by hand. If needed add additional soil and water again.
 
Normally plants will undergo very little to no shock when transplanted in this manner (in veg) but it would not be an injudicious thing to do to use a product like SuperThrive or something with the same general properties because they will reduce plant stress helping them to overcome it quicker and easier.
If in flower if a product like SuperThrive is used I would suggest the minimal suggested ratio of SuperThrive used only once. SuperThrive causes flowering ornamental plants to last longer by slowing down the flowering process, so if SuperThrive is used much during flowering marijuana plants it will increase the overall length of flowering time.