I forgot everything, and duolingo thinks I still remember it.
So I started the japenese course on duolingo a long time ago, I didn't use anything but duolingo to "learn that language". I couldn't retain any of the advanced lessons, so I tried the first lesson. It turns out, I had leveled up that lesson a lot. It was more review based than learning based. I probably could end up jumping back in, and struggling for the first day or two, but starting fresh would be the easiest. Is there any way to reset my progress on a language?
Settings > Learning Language > Reset or remove languages > Reset progress next to Japanese.
Settings can be difficult to locate, so I'll add this little extra note. :)
On the desktop version of the website, hover over your username where it appears in the blue bar at the top of the screen. A menu will drop down. From there, select "settings". (And the rest is mapped out by Tundra_. Thank you Tundra_!)