Immersion is an important step that is often a "must do" in the process of acquisition.
It is not always necessary, but: are you planning to visit the country where this language is spoken? Immersion exercises may signal to you whether you are capable of making that leap.
I've been bilingual in Spanish since high school, but not until 2008 did I encounter a situation of immersion. I've worked in a bilingual office setting, and I found that it was often easy to communicate face-to-face with Spanish speakers, because I could lip-read, and make gestures, and fall back on occasional English expressions that they are capable of knowing.
But when I traveled to Catalonia and we went off the widely-travelled tourist areas, I was required to know Spanish, and even Catalan, for the road signs, businesses, menus, etc. So it was as much immersion as I could get, and even then, I had a native for my guide, and she was an English teacher, and so she was very good at whispering in my ear about when waiters were simply being rude or prejudiced about my silly Mexican dialect.
So yes, it depends on your use cases, and I can see why it would depend on introverted/extroverted personality whether you can handle it, but when learning foreign languages, consider whether immersion will be a foreseeable situation, and try to experience it beforehand, because it can be diagnostic, if not helpful.