Discovering new abilities in an unorthodox way

The second I managed to throw my first fireball, it's level increased. But those progression points… I wonder how many of them do I get per single throw?

"Fireball"

With the spark of flames igniting from my energy on top of my hand, I once more pushed it away with a sweep of my energy. Limiting the force that I applied on it this time, I managed to considerably slow down it speed to a point when I was actually barely able to follow it with my eyes!