I agree that Jesus was like us in all ways but sin. However, I don't understand the bit about Mary. Doesn't the Bible say that we all have sinned and fallen short of the glory of God? (Romans 3:23). I've read several translations, but never found one that says that we all, but Mary, have sinned.
It's Catholic Doctrine that Mary was conceived without Original Sin on her soul (Immaculate Conception) so as to be the Mother of God. If one really thinks about it and ponders it ,it is the only way that makes sense. We also believe that Mary was ASSUMED into heaven, Body and Soul because she was the sinless Mother of God.