From my experience i would say not to start on the い adjectives before knowing all of the な adjectives.. i totally burnt out doing that in february and only started again 3 days ago…but then again everyone is different. if you know most of the na adjectives and you don’t have much left then go for it, but otherwise i would say do something else. i’m not sure about the review early function on anki.. i’m looking into it so i’ll tell you if i find something. :)