do i still need to fertilize if i find good potting soil?

my plants are 2 weeks old and i guess they're big enough to be transplanted.
My question is that " Do i still need to fertilize my plants after transplanting them in fine soil " ?

nope. you sure dont! if you're going into well cooked organic soil thats ready for water only, you'll be fine. On transplanting, see about picking up some mycorrhizae. dust your root ball with the mycorrhizae when you transplant to ease transplant shock and help roots establish quickly in the new home. best of luck to you!
oh, and on the soil note--doubtful you will find something prepackaged from a company that will need no amendment whatsoever, unless that prepackaged purchase is pre-fertilized. you will most likely need to supplement the nutrients at some later point in the grow.
be easy,

If such things are unavailable, in India, I'm sure a local farmer/gardener could recommend a local alternative.