There's not much that can be done? You can't get her to share your nostalgia because that's not how nostalgia works. If she was a gamer, she could learn to find the relationships between titles like the Zelda/Metroid influence in Dark Souls or the Half Life influence in Dead Space. But if she's a non-gamer, the best you can probably do is explain that those relationships exist, give examples, and see if you can find any older titles that are legitimately still fun today (Doom and Super Metroid are potential candidates).