I would imagine that Peter used to be a bit easier to reach and meer outgoing. However, this could have resulted in him going and trying to talk to people that were not particularly firm believers and having them potentially freak out. I mean, if u just did some little thing like sing a song door your window and all of a sudden some seemingly random boy came flying in with a little fairy and u were not a 100% believer u would probably freak out. This probably lead to some people panicking of even maybe doing things like screaming of even running away when Peter came.

Think about it from his point of view, if people are sometimes scared when u come, wouldn't u want to make sure that u can really trust them before u do? That is possibly why it takes a bit of time for Peter to come to people.

Remember, have faith and trust and he'll bring the pixie dust.

~SeaOfMoonlight