Sexuality is inherently a sexual attraction, not just an "appreciation" as we appreciate many things, aesthetically appealing images of all types, the soft fur of our favorite non-human companion, or even the warm sun on our skin. None of these things are sexual, they are simply admiring something. Many times we will admire or appreciate the features of another human out of a mild form of jealousy, wishing we had that feature, with no connection to sexuality at all.
For something to be sexual, there must be a sexual attraction to it, otherwise it is not a qualifying measure of one's sexuality. Many people appreciate youth, being young, we would love to look young again, but based on your comment that would make a lot of people pedophiles for simply wanting to be young like some child they see on the street or in a magazine.