3月6日はまひろちゃんのお誕生日です。おめでとうございます！
Pixiv版1話から連載7年目らしいので7歳の姿（女の子ver）で。

March 6th is Mahiro-chan's birthday. Congratulations!
It's been around 7 years of serialization on Pixiv, so here's a 7-year-old version (as a girl).