im pretty sure its legal in japan. rin was 14....
this is from wikipedia:
The age of consent throughout Japan is generally 18, but 13 in certain circumstances, due to a combination of national and prefectural laws.
The Japanese Penal Code sets a minimal age of consent of 13.[33] However, all prefectures and districts have (largely similar) "obscenity ordinances" (淫行条例) that forbid "fornication" (淫行) with anyone under 18 years of age, but exempt *** in the context of a sincere romantic relationship or with parental approval.[34]
The age of marriage is 16 for girls and 18 for boys, with parental consent, or 20 otherwise.
XD