I started using WaniKani back in high school, but once I started university I ended up never getting a chance to continue due to a busy course load. Now that I’ve graduated, I’m considering resetting my progress so that I can get back to WK without worrying about having forgotten burnt items. However, I did take beginner and intermediate Japanese courses during my uni years, which used Genki followed by Tobira; thus, I’m not sure which level I should reset to. Is there something akin to a “placement test” that I can use to gauge which level would be the “optimal” reset point for me?
At level 13 you should have a few hundred kanji and maybe a thousand or so vocabulary entries, why not try to do you reviews and see how you feel about it? If it’s easy you should go through the backlog quickly enough, if it’s too hard you can always reset back a few levels.
BTW with apps like Flaming Durtles (and I’m sure user scripts) you can do your reviews in “Anki mode”, where you just have to say whether or not you remembered the meaning/reading instead of having to type it out. That can massively cut on the review time if you want to quickly get up to speed and discard stuff you already know well. Then you can return to the usual review method once you’ve cleared your backlog.
What I did for my reset is to use a reorder script to take reviews in increasing level order. When I hit a wall (failing too many reviews) the level of the troublesome items is where I did reset.