I started learning Spanish at 33 and am fluent to a degree that I could operate professionally. But I had the advantage of immersion when I spent a couple years in South America, where I met and married a Latina. Having a private teacher to correct mistakes helps. We now live in the US and spend some days speaking only in Spanish so that I don't get rusty.

I started learning German a few years back. It is a much more difficult language and I think without taking a lot of courses and having consistent conversation partners, there's no way I'll achieve fluency. I listen to podcasts and maintain my streak on r/WriteStreakGerman, but I'm still only somewhere around an A2 level.

"Fluent" is really a difficult concept to solidly define. If you can hold lengthy conversations with people, how are you not fluent? You don't have to speak perfectly to be "fluent." Even native speakers make mistakes. In my opinion, if you can follow the flow of a conversation and contribute to it in a meaningful and understandable way then you're somewhere close to fluent at the least.