Michelle Obama posted a candid family photo to celebrate her mother Marian Shields Robinson's 84th birthday on Friday, while accompanying the snap with a heartfelt tribute to her parent. The former First Lady credited her mother for teaching her how to "think for myself, use my voice, and show up authentically in this world" and called her the "ultimate role model". READ: Michelle Obama's $191k childhood home is nothing like The White HouseThe photo shows the two laughing, while both dressed in