harukotoNewbie
Jack-O start casually practicing some japanese regardless if you have interest at all. it's not hard to learn the first two alphabets, takes a couple days and some practice reading and writing over time. get to really learning most kanji when you're ready to actually commit. it saved me a lot of time. i learned one other language while getting the basics of japanese out of the way, arguably the fun parts, the only fun parts. a language like dutch wouldn't get in the way at all either.
if you watch anime, with dutch subtitles and have learned a lot of japanese you might find yourself relying on either language when you don't understand whether you're reading/hearing something you haven't learned. that'll help you learn more. i did this with one target language and watching anime. it made me happy when i would look away and would just understand the japanese without looking at any subtitles. second greatest feeling of my life.