Oh that's not a big deal at all. Pokèmon in this setting evolve when they're ready, when they've matured sufficiently. This may mean that they've grown in strength or intellect or simply that they've found their place in the world... anything that can mark a turning point in one's life. It may be something that happens all at once, in a fit of passion or rage... or it may be that the pokèmon will slowly gain a sense of nearness, of maturity, until one day it's simply [b][i]time.[/i][/b]