Jedi powers, as with any skill, take time to master once learned. Raw talent can be disguised as mastery, but can still be refined and improved. Rey is not at a point where she can be considered a Jedi. She saw how Kylo did things and copied him. And now that I think about it, Kylo trying to force her to reveal things and her fighting back and reading his mind, could have resulted in her absorbing some of his Jedi training. But it means she knows these things are possible. So not just her life on Jakku, but her reading of Kylo’s mind has given her far more than Luke had to start with. I mean, it was after that point in the movie that she started doing things. She pulled the memory of Darth Vader out of his mind and how he wanted to be like him. As to how she managed that, I would have to say raw talent and instinct. Kylo started probing her and she could feel it (you can see it on her face) and she was able to block him and then turn around the do the same to him. He wasn’t ready for it and was quite surprised (again, you could see it on his face) and failed to block her.
But while Rey shows is that she has learned these force skills, she has not mastered any of them. She has used them once or twice and needs guidance on how to use them. Not just how to literally use the powers, but the ethics of using them. Only when you have the ethics down and the philosophy of being a Jedi can you be considered a Jedi. Until then she is just a very powerful Padawn like Anakin. But to be perfectly honest, I believe that JJ Abrams took one huge shortcut with Rey. She was created as a Jedi from the start. She has ethics, can fight, can fly, and has disciple. Even without force powers, her character was basically a Jedi already. She just needs to complete what she needs on top of who she is. Her arc in TFA was beaking from Jakku and being willing to grow. Her arc in TLJ is facing that her parents were nobody special in the galactic scheme of things and that they abandoned her. Luke is in TLJ, who she needed to break her dependence on others. Rather than wait for Luke to change his mind, she takes the initiative and steals the Jedi texts and leaves to teach herself. From where she was at the start, that is a huge growth for her character. Yeah, the force seems to come easy for her, but other things aren’t so easy and that is what her story is.