Innate Talent or Beginner's Luck

I was sitting on the shitter reading a book the other day and I thought occurred to me, although it is kinda hard to put into words. I shall try.

Have you ever been in a situation where you started something new, something that involved a skill set you have not used before, and you were just really good at it. More established people were impressed. Then, as time went on and you learned more about the rules and structures around whatever it is you were now doing, your 'innate ability' kinda waned and you became more average?

I'm probably not describing it really well or coming across as being a cocky bastard. Let me try a different tact. Have you ever come into something new knowing nothing about the way it is supposed to be done and performed surprisingly well? There, that sounds better. Happens all the time in sports. New QB comes in because the other one was injured and turns the game around. Then the next week he tanks and you find out why he was the backup in the first place.

What the hell is all that about? Is it some innate ability that was never tapped before or just beginner's luck? And what is beginner's luck?

I feel like it is more than that. I like to believe that because you don't know what you aren't supposed to be able to do, the pressure is off and you are free to just do. So a lot of the stress/anxiety/whatever is missing that occurs during later attempts.

Does this make sense to anyone else or was I pushing too hard on the shitter? ;)