you can assuming your original pot is large enough for the final plant. however it is easier to work your way up, as you will start with more seedlings than you will finish with, and space is often a concern
well i got pots ranging from 3 gallon up to 12 & 15 gallon pots i was thinking about starting the seeds in the big ones and then transplanting and using some 6 gallon pots for the ones i don't want to transplant
I use 3 gallon pots as my final pot size for growing. I grow mostly indicas and this size seems to be just perfect. Last grow I had 12 3 gallon pots under 400w HID ended up with 7 females and that size was just perfect for them
Indoors you don't need anything larger than 5 gallon pots, unless you have 30 foot ceilings to work with