To be "fluent" in a language, you need to learn the words. (Aside from also learning the grammar and idioms and becoming able to pull them from your mind without needing to think about it.) To be able to converse readily on any topic that might come up in a commonplace conversation, you might need to know something like 15,000 words. Actually, that is a rather sparse vocabulary. A native speaker knows more like 20,000 to 35,000 words. So do the math. Think about how many words you would have to memorize per day.

A language is a lifetime project. However, if you are less than, say, four years old, you might become fluent in a year or two. After that, the brain loses elasticity.

My answer, for what it’s worth, is that you couldn’t do it in three years, unless you go to live in an English speaking country and speak English with native speakers every day. Three months on the internet or taking classes, not a chance. You could prove me wrong though.

No, but you can certainly start getting the foundation for fluency in 3 months. English fluency will take years of hard work!!

i speak it every three months. every year. every day ;)