Saudade said:
german is my first option if i ever try learning third language. how much does it differ from english and how long would it take to learn it by yourself?
Learning it by yourself is really difficult tbh and native Germans can't really help you either. There's so many rules in the language they follow that they just know from birth that they can't explain. The best route is to find someone who speaks English and German and have them help you.
It's quite different than English despite a lot of words being the same and them both being Germanic languages, which helps. The difficulty lies in all the rules conventions you have to follow that don't exist in English and memorize the male, female and neutral forms of words and when to use them. Get those down and you're pretty much set tbh, English and German have maybe like 30% of words in common and the letters are always consistently pronounced unlike English or French. As in J is always the "yuh" sound and "g" is always the "guh" sound. It helps a lot tbh