To quote Mark Twain, "The two most important days in your life are the day you are born and the day you find out why."
Whenever I hear this quote mentioned, I feel this is speaking about cultivating certainty. When you can pinpoint your purpose, the reason you are meant to exist, you make your decisions and take actions with certainty. When we are faced with a multitude of choices, we may spend time vacillating between our options. When we have certainty, we have less friction in coming to those decisions.
I feel a lot of people are on a quest to determine the one thing that they have been put here to accomplish. I like to think of it more as a "Renaissance (Wo)Man" way of life. There isn't one thing, there are many things, and discovering each new area of our brilliance allows for us to keep living a richer, fuller, more meaningful life of certainty.
When we look back on the span of years we've accumulated up until this point, we can probably identify several pillars of certainty that have built our present level of expertise. There may have been key turning points that make these periods more vivid in hindsight. When we can look back and admire our phases, the good ones and the bad ones, we've probably been able to accept that we not only had certainty in that moment--no matter what the outcome of a situation later developed--we acted at the time with our certainty. If we look back, we probably even had some idea of what the reason for a blunder would have been before we set out, and with even knowing that possibility existed--we did it anyway. That's certainty.
Certainty is not choosing something incorrectly, or changing our mind about something later, it's truly cultivated with our experiences. Certainty is acting in the moment with what is best, based on all of our experiences to now. I can look back and clearly say, I shouldn't have done that thing, but that thing helped me know later with certainty that I will never do x thing again.
If we look at people who are well decorated with their contributions to the world; people who've experienced amazing levels of success in multiple venues, we can see with certainty, multiple paths are not just possible, but the process to our greatest levels of certainty. It isn't the one thing you can be the world's greatest at out of the gate. It's all of the things that you can be amazing at so you can better know (with certainty) where you hold the most brilliance.
So, go ahead; you have permission to keep acquiring knowledge and skills so you can achieve your greatest ambitions... all of them. I'm certain of it.