Knowing more than one language does not mean that the language can speak and understand. From the moment you can speak two languages balanced, your brain starts to work in a very different way.
You have heard that the right lobe of our brain is more active and dominant in the logical processes of the left lobe in emotional and social areas. But this is not a constant process. Especially as one's age progresses, which one of the lobes will perform the function.
Learning a language is melting the function of two lobes in one pot. As you learn and speak a different language than you know, both lobes are active. So if you want to learn the language, the sooner you do it, the more likely you are to learn it so effectively and quickly.
Adult language learning also has its own advantages: According to experts, people learning and communicating with a language over a certain age tend to be more analytical and less logical. Let's leave you on video without letting your words go too far. You can open the Turkish option from subtitles.