I usally ask this by I add another part to it. If god is perfect then why does he change his ways in the bible 2 testaments god didn't get it right the first time or something when I read the bible in my eyes I don't see a perfect being I see a being that has made lots of mistakes
That's a good question, one to think about. God didn't make a mistake concerning the two testaments. The Old Covenant, which had the animal sacrifices and more severe punishments for sin, was intentionally made that way for a few reasons. First, it was necessary for us humans to see just how much of rebels we are toward God. The Law of the OT is traditionally said to have 619 laws to follow, and the Jews probably broke all of them. Secondly, the punishments were as severe as they were - sometimes requiring death - to demonstrate just how severe our rebellion is toward God. Third, the Old Testament was used to foretell the coming of Jesus, the perfect sacrifice for our sins. The Law itself is a sort of metaphor for Jesus, in addition to the several hundreds of prophecies about Jesus. It wasn't the right time for Jesus to come yet, so until his arrival, the Law as found in the Old Testament is what was used.
The New Testament records the completion of God's plan, started with the Old Testament. With the punishment of our sins completely put on Jesus and not on us, there was only grace and mercy left to be given us. There is no mistake, just Phase 1 (Old Testament) and Phase 2 (New Testament) of God's plan.