Well, it could also happen that Peter's Spider - Man suit technology gives him away. Maybe the Avengers have some advanced tech - sensing equipment, and when Peter is around in his suit, it gives off some unique signals that the Avengers pick up on. So, they start to look into it and eventually figure out that Peter is Spider - Man.
Tony Stark would probably be both proud and a bit worried. Proud because Peter is this brilliant young mind who has managed to be a hero on his own, but worried because he's just a kid. He might start to hover over Peter more, offering him better tech and trying to mentor him more closely. Captain America would likely be very accepting. He sees the good in people and would be happy to have another brave soul on the team. He'd probably offer Peter some words of wisdom about using his powers responsibly. Thor might be a bit clueless at first. He doesn't quite understand the whole 'secret identity' thing as well as the others, but once he gets it, he'd be all for having Peter around. He might see Peter as a little warrior and be eager to train him in his own Asgardian ways.
Well, in a lot of such fanfics, it often starts with Peter making a small mistake while being Spider - Man. Maybe he leaves behind some evidence that's a bit too obvious, like his school notebook with his name on it at a crime scene. The Avengers, being the sharp - eyed group they are, start to piece things together. Tony Stark might be the first to suspect something, using his high - tech gadgets to analyze the蛛丝马迹 (clues). Once they figure it out, they could either be super protective of Peter, seeing him as a young and inexperienced hero, or they might be a bit wary, not sure if they can fully trust this new - found Spider - Man.
Some Avengers might be protective. For instance, Captain America could immediately start giving Peter advice on how to better handle his dual identity and keep himself safe. He might offer training sessions to help Peter improve his skills as Spider - Man.
One idea could be that the Avengers are initially shocked but then become very protective of Spider - Man. They might start to train him more carefully, like Tony Stark making sure his suit has extra safety features. Another could be that some of the Avengers, like Captain America, take on a mentor role, teaching him about responsibility and heroism in a more age - appropriate way.
The Avengers could find out who Spider-Man is in fanfiction by a trusted insider accidentally spilling the beans. Or perhaps a villain uses this knowledge to manipulate the situation and forces the truth to come out.
Well, with the Avengers knowing his identity, Peter's relationship with Natasha Romanoff could be really interesting. She might teach him some spy - like skills to keep his identity even more hidden from other threats. As for Thor, he could be a bit clueless about how to deal with a young hero like Peter, but still offer his support in his own way. And Peter's relationship with MJ would also change. She might be more involved in his superhero life now, which could bring them closer together or create some new tensions depending on how she reacts to the whole situation.
One interesting storyline could be Spider - Man teaming up with the Avengers to fight a new super - villain that's a combination of different powers they've faced before. For example, a villain with the strength of the Hulk and the mind - control abilities of Loki.
One way is by getting involved in Peter's school life in a more official capacity. Maybe they could arrange for some anti - bullying seminars at the school. Natasha could also train Peter in stealth and evasion techniques so that he can avoid the bullies more easily. Thor could even offer to be Peter's bodyguard for a while, at least until the bullying situation is resolved.
The Avengers would be very concerned. Captain America would immediately take charge of the situation, trying to keep everyone calm while they assess Spider - Man's injuries. Iron Man would start scanning for the best way to treat him, using his high - tech equipment. Thor might offer some of his Asgardian knowledge of healing, if there was any. Black Widow and Hawkeye would be on guard, making sure there were no further threats while the team focused on Spider - Man.