Because St. Peter is the Rock upon which Christ Built His Church.
Yes, Saint Peter is really a saint. If he were not a saint he would not have that title.
St. Peter would be your primary patron saint.
Saint Peter of course, one of Jesus's disciples, who was chosen by Christ to be the first leader of the Catholic church, although it would have just been called the Christian one then. The Basilica sits atop the tomb of Saint Peter and is a memorial to him.
Peter would have been about 30 years old when he became an apostle.
Peter was a martyr so the color of mass vestments would be red.
he is 2012 years old
To be a saint the person must be a Christian and to be a catholic saint the person would need to be a catholic Christian. However not all catholics are saints.
The canonization process did not come into play until about the 12th century, long after people already considered Peter a saint. He would have been declared a saint by the local Christian community shortly after his crucifixion. This probably occurred in Rome.
There are no statistics kept that would answer this question.
If he were still alive today he would be about 2015 years old.
If Valentine was a seriously sinful person he would not be a saint.
The closest I can find is St Bernard of Menthon who is the patron saint of mountaineers.