From DoA ABJD Wiki
According to March's official description,
She was born on March 1st, 2008. March is such a nice month, icy and snow melts, sun warms the field, grass grows and trees turn green. People go out to enjoy the warm spring after long cold winer. Hope Bobobie girl March brings spring, hope and good luck to all people that love her.
March at Bobobie Doll Mall