I'm a bit confused on this question. If you're watching your favorite anime, then wouldn't you be considered within the target audience anyway? What is it about the anime that you define it as your favorite?
For me, as an example, I'm a 49 year old woman. My favorite anime is Magical Girl Lyrical Nanoha, hands down-- specifically the first two seasons. The story is cute, dramatic, has a tiny bit of romantic tension, and I guess an argument could be made for a tad of loli in there??? But there's also the diverse magical attacks, the darker aspects of entire magical realm story-content. I fell in love with this anime fifteen years ago. But I think the story was probably targeted more towards girl power, and adolescent boys maybe?
Now, even though I certainly don't fit within the girl power demographic, I'm quite comfortable in my own powers of imagination and creativity to slay monsters and demonic Capitalist forces within the world on my quest towards world domination, and I know I'm not a teenage-boy either, but that's not going to force me to question my taste in anime, and certainly I am not going to stop watching it -- I'll probably watch it about another 9,000 times before I finally disintegrate into dust molecules.
So why is Magical Girl Lyrical Nanoha my favorite anime? Honestly, probably because of a single character, and she's not the main protagonist either. I just happen to have lived through some of the dramatic events similar to what Fate had to endure. So, I guess, you could say that I'm hooked on this particular anime to see how her life unfolds, so that I can see how my life may also unfold (despite being like double her age now?) But also, this is a favorite because there are so many time gaps that it's a paradise for fan fiction writers like myself! Well, enough babble and rambling from me. This is getting way too philosophical even for me!