First, look at this song:
Eternal Blaze by Nana Mizuki. It's one of the opening themes to Mahou Shoujo Lyrical Nanoha A's. The song and anime were both originally released in 2005.
I first heard this song in 2007 (or around there. Maybe 2006, maybe 2008...something like that). However, I remember hearing the song in the 90s. My guess is maybe 9 years earlier, but it could have been more. So that proves that I couldn't have heard it before that first time I heard it in 2007.
It couldn't have existed in the 90s, but I do have proof I heard it then: I knew the lyrics of the full version of the song when I first heard it in 2007.
Now, I couldn't have heard any Japanese songs until 2002, when I first started watching anime on Adult Swim. I live in America. Most Japanese show openings were dubbed over in English in the 90s. I also didn't start looking up full versions of anime openings/endings until 2006, when I first found Youtube. So this disproves that I heard it in the 90s.
The riddle: find an explanation for this.
