oh wow how Lucky I am ... for reading this XD
That reaction was super cute, they're both sooo cute!
A minor
Is she really?
Under 20, which is age of majority in Japan. Age of consent is not above 18, though (yes, national law is 13 but IIRC no prefecture is that low). They're in the clear but Tsubasa is still very young, 19 if I remember.
Honestly I'm not sure what it really amounts to, maybe you have to be 20 to vote. You can quit school after middle school (15), you can get an apartment and all the other stuff I think, so the only thing other than voting is buying alcohol and cigarettes.