[Tainnor]

I you want to get a head start on something, Kanji is probably a good idea - there are about 2000 of them in common use (more, if you read more advanced stuff or in names), and teachers probably won't have a lot of time going over them. Plus, you essentially just have to memorise them, something you can only do on your own.

There are several ways of learning Kanji, each with their benefits and drawbacks, such as WaniKani, Remembering the Kanji, Kodansha Kanji Learner's Course, etc. Ultimately, Kanji are painful and time-intensive to learn, so none of these will be perfect, but you can maybe spend some initial time trying to find out which works best for you and then just stick with it.