Blaine, of course, remembers meeting Kurt. How could he not? When galaxies collide, the fallout is colossal.
What he doesn't always remember is that he's met all of Kurt's New Directions friends before.
Some of those meetings happen in different worlds, so it's all fuzzy in Blaine's head and the details aren't clear, nor do they necessarily make sense.
Some of the kids remember Blaine and some of them don't. The feelings they bring up are not always positive, and the kids don't always act as they ought to. Some of these stories have happy endings, and those are moments to be treasured, counted out, like his mother's creamy-white pearls; the ones she wears with the black velvet dress, with the diamond studs that glitter like stars.
Blaine remembers some of them fondly. And there are a few memories that cause him pain. He learns, eventually, to let the drama all go. Even the painful encounters have burrowed themselves deeply into his neurons, too, so whatever he does learn from them - what he does remember - he keeps forever.
Blaine doesn't always act as he ought to have, either. He's definitely not proud of those times.
And there are some meetings that Blaine doesn't remember at all, or that he knows even happened, somewhere out there. But that doesn't mean that they aren't important, either.