Question about Minami Kotobuki and gravure

Watching Oshi no ko I discovered that Minami Kotobuki is a gravure idol, but it's underage! How is is possible that in Japan a minor can be a gravure model, which means that they take sexy pictures of you half-naked? She is 16 yo, and I found out that even younger girls can do that job. Isn't that ped0p*ilia?