You can transfer your plant anytime but make sure you are careful not to damage the root hairs that's where the plant absorb nutrients.
The way I do it I get me a long knife and stick it going around the pot to loosen the plant from the pot. I invert the pot and get the plant out or if I have that black plastic pot I just cut it in 3 places to get the plant out.
Then I get a pot size next bigger put some good soil- well draining be sure 1/3 perlite, 1/3 pine bark 1/3 top soil and add osmocote fertilizer or steer manure mix it well add it to the pot a third full and put in your plant. Now flood the pot with Warm water I mean soak the soil so no air is trapped inside. Then put your plant in diffused sunlight for 2 to 3 days and you are good to go. Water again when the next top 2 inches is dry.

Bencelest-

Thank you so much for the information. We did it earlier today. I appreciate your help. Hope to have some lemons this year :):)

Beca