Same ****, different label.
No, it's an entirely different religion.
It's from the Old Testament
Correct. It's from a subsection of the Old Testament called the Law of Moses, which was only relevant to the Jews.
In the New Testament, Jesus teaches that nobody is required to keep the Law of Moses anymore. Christianity was founded upon this premise, which is why Christians do not keep the Law of Moses.
are you telling me Catholics don't read or believe in the Book of Deuteronomy?
No, that is not what I am telling you. What I am telling you is that the Law of Moses is not part of the Christian religion and Christians are not required to observe it. If you had actually taken the time to learn what Christianity teaches, you'd know this already.
P.S. the passage I used came directly from a Catholic website.
Irrelevant. You need to learn more about Christianity. Specifically: learn why it's different from Judaism.
**Disclaimer** I am not a Catholic.