I registered some domain names almost or over a year ago, i did not make them private domain registrations.
Id like to do that now, but Im wondering, when you google my domain names there are several websites that have the whois information, which displays my name, if i were to now make my current domains private, would these websites pick up on that and eventually stop displaying my information?
No - they would show the current whois as private - but some allow a check on previous whois details too. (It would of course not be obvious that the change in whois details did not mean a change in ownership of the domain.)
yes with the same provisos as mentioned by IanTurner.. to see ownership "history" you'd have to pay ..Google as a registrar would not have to pay ( if that is your concern ? ) as they have/had access to the public data ..and thus know the the history..unless they wipe their records ..<= highly unlikely scenario ;-)