I would imagine that Peter used to be a bit easier to reach and più 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 te just did some little thing like sing a song da your window and all of a sudden some seemingly random boy came flying in with a little fairy and te were not a 100% believer te would probably freak out. This probably lead to some people panicking o even maybe doing things like screaming o even running away when Peter came.

Think about it from his point of view, if people are sometimes scared when te come, wouldn't te want to make sure that te can really trust them before te 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