You want to leave them in those pots. They are fine there. Too big too soon and you will stunt the growth of the plant. You could have started them with less soil / smaller pots. It is hard to gauge the size of those things but I'm guessing you can leave them in those until they are at least 6 - 8". Otherwise the plant will focus all energy on growing roots below ground. Just be sure that those cups have holes in the bottom for drainage.

Check your Ph first. They look a little young for nutes at this point.