You will become different. Whatever measures by which you discern 'better' before, will be irrelevant, almost laughable to the person you become. And beware too that growth can itself become a preoccupation.
If you have goals like be more productive, make more money, change the world, be more liked... then prepare yourself for at least the possibility that you will, in the course of real growth, end up rejecting those things as silly.
edit: accidentally posted as reply to wrong comment