I have a cousin named Alicia whose nickname is Aya. I wasn't sure what the name meant in reference to her (I thought it had something to do with the Ayah from The Secret Garden), but now that I know it's Japanese, I understand where she got it. She likes the language of Japanese (she's really into animes and mangas and always draws anime-style characters), and the meaning of "color" or "design" suits her well. It sounds like an artistic girl who can go between two different types of behavior, crazy and silly or dead-serious, both of them suiting her equally well (this is what my cousin does). I'd definitely use it.