You need to get this fluent thing out of your head, it's incredibly rare to master fluency in a second language after the age of 14.
It's not that difficult to become good in a language at any age, good meaning you can have conversation about subjects you have an interest in.
Language learning is time consuming. Some languages are easier than others.
The secret to language learning is: repetitio mater studiorum est
One thing I find with speaking different languages is it's confusing. I was watching a film the other day and turned to the wife and asked her what the fuck was going on? She answered You should know it's in English: my brain was translating it into Spanish.