Boku Girl

Boku Girl is a 2013 manga with at least 25 chapters written by Sugito Akira and is serialized in Shuukan Young Jump.

Plot
Mizuki gets confessed to by a boy in front of a special Mirror. Loki decides out of boredom to mess with Mizuki and turns him into a real Girl.

Other Sources

 * https://www.mangaupdates.com/series.html?id=105986

Other Wikis

 * w:c:AnimeBaths:Boku Girl