"Uh, yeah no, not quite like that." He shook his head, and he sighed slowly wishing that they had a more mutual understanding of the world, it'd make all of this much easier in the explaining. "MI5 and things like the CIA or the FBI they're government funded, they're a little more into the spy business than the Avengers or the X-Men." Peter wasn't fool enough to believe that they didn't delve into those sorts of areas of course, but at their heart - at their best - that wasn't what they were about.
"The Avengers is a group of people who do their best to help keep people safe." He explained, "They're people who have super powers," Yeah this was going to go really well, Peter could tell, "Or they were enhanced in some way." He was going to have to tell her about himself and even then Peter knew how well that was going to go. He remembered how unbelievable it had been when he'd first been bitten the idea that he was suddenly different. It didn't make sense even to him and he was the one changing. Getting someone else to believe was a whole other ball game.
"Like me, I was bitten by a radio active spider." He said finally, biting the bullet. "It's ridiculous as far as origin stories go, I know, but something about the spider changed me, I got strong, and fast and eventually I decided my new abilities would be best used to fight crime, to try and make the world just a little better," He didn't go into the whole Uncle Ben thing of course, but it had been a push he'd needed at the time. "Most people here have a story like that, something unbelievable that made them something more than they used to be, and they found themselves in a similar position - they started helping people."
"The problem is that when people start becoming enhanced the world does too, I guess it was only a matter of time before that bled into to the space between dimensions." Something from one dimension was bound to effect the others sooner or later.