Peter might also be a bit scared. After all, the Avengers are some of the most powerful people on the planet. He could be thinking that they might attack him without listening to his explanation. So he would be cautious in his movements and words, trying to stay calm and convince them that he's on their side.
Peter would probably be really shocked at first. He might try to quickly explain who he is and that he's not a bad guy. For example, he could start blabbing about being Spider - Man and how he just wanted to meet the Avengers.
He could be a bit defensive. I mean, he's just a kid who looks up to the Avengers, and being accused of being an intruder is not cool. So he might start showing off his powers in a non - threatening way to prove that he's not there to cause trouble. Like shooting a little web to catch something falling and saying 'See? I'm here to help!'
Well, it could be his age. Peter is relatively young compared to the other Avengers. They might assume that a young person in their highly - secure area is an intruder. Also, if he showed up at a time when they were on high alert, like after some threat or security breach, they'd be more likely to suspect him. For example, if there had been a break - in attempt recently, and then Peter just swings in out of nowhere.
Peter is likely to be in awe. He might be a bit nervous at first, but also extremely excited. He has looked up to the Avengers for a long time, so meeting them would be like a dream come true. He would probably be stuttering a bit as he tries to introduce himself and show his respect.
He might also get angry. Peter has a strong sense of justice. If he feels that the Avengers are being unfair, he could stand up to them. He'll use his quick wit and his powers to show that he's not going to be pushed around easily.
They might be a bit surprised at first. Maybe Tony makes some jokes about British tea and bad teeth, but in a friendly way. Steve would probably be intrigued by Peter's different cultural background and might ask him about British history.
Peter might be very defensive at first. He could argue back, trying to explain his actions. After all, he is a teenager with his own ideas and he may think that the Avengers don't fully understand his perspective.
Tony Stark might use his quick wit and technology. He could immediately scan Peter to make sure there's no physical danger causing the hyperventilation. Then he'd probably crack a joke to try and calm Peter down, like 'Kid, you breathe any faster and you'll fly away like a human jetpack.'
Peter usually blushes a lot. Since he's a shy and somewhat awkward teenager, his face turns bright red when the Avengers embarrass him. He might stutter while trying to defend himself or come up with an excuse.
Peter may initially be angry. He might feel that Maryjane didn't give him a fair chance or that she misjudged him. However, as time passes, he could come to accept the rejection and try to move on, focusing on his own life and other relationships.
Some Avengers might be initially shocked. For example, Steve could be a bit taken aback as he tries to understand how this could be possible. He might be concerned about the implications for the team dynamics.
Natasha Romanoff could show her emotions in a more subtle way. She might look at Peter's old things and a small smile would cross her face as she remembers his innocence and determination. Thor, on the other hand, might become more determined to protect the world in Peter's honor, as he respected Peter's strength despite his young age.