Most of the women available for romance in Persona 5 are your fellow high school students. But not all of them.
PERSONA 5 STORY & RELATIONSHIP SPOILERS AHEAD
Taking the role of a kid in his second year of high school—which in Japan would put the player at roughly 16-17 years old—Persona 5 surrounds you with single girls who might befriend you, may become attracted to you and also potentially follow you inside people’s hearts on daring heists to save the world.
This is all normal and expected for a Persona game. Romance isn’t just an option in this series, it is—like Mass Effect—for many fans an endgame in itself, a statement on how you approached your playthrough and the decisions you made. “Oh, you dated her? Well, I kissed her”, etc etc.
Persona 5 is different though. It’s a darker, more mature game, both in its tone—it opens with player being beaten and drugged before leading into some sexual assault allegations—and the company it keeps, with less of an emphasis on your fellow kids and more opportunity to forge relationships with adults.