Day one? Day two?
"The light. It's always been there." It will guide you." "Something inside me has always been there. But now it's awake."
So what exactly is the difference between TFA Rey and TLJ Rey? How has she mastered the Force? In TFA she uses telekinesis, and in TLJ she uses telekinesis. Nothing has changed.
Which is exactly the point. If she's always had this power and nothing has changed, then there is no character growth. Luke may have had the power innately within him, but he had to learn what this power was, how to use it, and most importantly to not use it for selfish purposes and risk falling to the Dark Side. You see the difference? A huge part of the difference between the two is that Rey's story takes place over a matter of days where Luke's journey is over a matter of years which allow time for him to have learned more.