This could all be fixed if it’s revealed she had a bit of training as a toddler by some forgotten survivor of the Jedi purge. 😉
I’d find that neither satisfying or necessary.
Unless knowledge of how to use the force transferred to her from her mind link with Kylo, the simple fact that she on her own thought to use the Jedi mind trick needs some sort of explanation…unless I am forgetting something.
I suspect that Kylo UNLOCKED her force powers during the interrogation scene. Her force powers were sealed by someone who left her behind on Jakku. A planet so remote that even old Luke Skywalker admitted that Jakku is pretty much nowhere. But who was it? My guess: it was Reys mother. When Snoke was actively looking for young untrained force users, Reys mother hid her on Jakku never to be found by Snoke. Snokes search was successful though: he found Ben Solo.
I’m really hoping we will see Reys mother.