Yes, multiple times.

I started learning English when I was 3 and can't remember ever not knowing it. I mostly read in English as a child, and didn't really discover what a great language Spanish is until high school. Side effect: I have had perfect IELTS and TOEFL scores every time I've had to take those (first time when I was 16?). It is my primary language now and has been since I finished college.

I decided to learn French when I was 9. I went to classes (where I was the youngest, nerdiest person) and listened to music in French. I was reading short novels in French by the time I was 14. Sadly, my french is very rusty now for lack of practice.

I decided to learn German when I was 18ish. I took classes on and off while in college and watched A LOT of german movies. I saved up all my work money, went to Germany for a summer, and basically force-immersed myself. 10/10 experience, so much so that I eventually moved there for a few years.

While living in Germany I decided to learn Portuguese and Dutch. Both were easy because I speak Spanish and German. Tons of media immersion, hanging out with random portuguese and dutch people (through language tandem type things), then some classes for both. I'm out of practice now, so my Dutch comes out sounding like German and my Portuguese is okay as long as I'm writing and not speaking.

I vaguely need to learn some Italian for work before summer and I've used Duolingo for that. It's slow though, so I might look up a language tandem group for it.

As long as you stay within the same basic family, it gets a lot easier the more you've already studied. There's a lot about Spanish and English grammar that I didn't understand until I'd studied other languages (but I'm super into languages as systems so YMMV). But languages are, at least IME, very much a use it or lose it thing.