[bringer_of_the_sun]

many girls in japan write their first names in hiragana/katakana because it's considered to be more cute. ^^ i think that's perfect for ayu's stage name.

kanji has many different pronunciations depending on the situation and even the person. アユミ, あゆみ, 歩み and 歩 are all perfectly valid ways of writing "ayumi". as for which version is "correct," that depends on the preference of the artist. most kanji will have multiple kun (native japanese-derived) readings as well as multiple on (chinese-derived) readings.