Catholics who is your mediator in sin?

Question for a Catholic. Who forgives your sins? If you say Jesus which is correct, why would you confess your sins to a priest? Why would you ask Mary to pray for you? Do you not think Jesus who is God by the way, can forgive you or will forgive you of your sins by dying on the cross? If not, He did not really have to do this, right? After all you believe there is a Purgatory and that Mary possesses power enough to influence Jesus to forgive you. Are you not worried that ALL your sins may not be forgiven because you asked EVERYONE BUT Jesus to forgive you? Read the Bible more please. Your salvation is truly at stake!