Quote Originally Posted by TheAbominatrix
Celes was infused as an infant (she says so as they're leaving Zozo for the first time).
Actually, I believe the line was "I don't remember, because I was asleep when they ... augmented me," in regards to where they draw the power to infuse magical abilities with, after Ramuh explains that other Espers are being drained of their powers but can't be fully drained until they die. However, I still agree with you and believe Celes was infused when she was very young -- I mean hell, how old is she when you find her? It had to be a few years before, at least.

After they did it to Kefka (probably as an adult), they revamped it, like boys from the dwarf said, figured it out, and did Celes right. Although maybe not as powerful as Kefka -- that may have been what the problem was, they tried to make him too powerful (and did), and his mind couldn't handle it.