Nothing Luke does in ANH is something only an expert pilot would be able to do, the most being his shot against the Death Star which was down to using the force anyway.
In what seems to be Rey's first time flying a ship she's able to navigate a Star Destroyer ruin with ease, something which I wouldn't even think Han would be able to do as easy.
1) Nothing implies that was her first time flying a ship, in fact the movie implies quite the opposite
2) She's been getting scraps off of Star Destroyers, it's logical to assume she'd be able to navigate through one.