That's good. Absolutely no one, not a single person, is or ever will be worthy of His sacrifice. Even if we become absolutely sinless, we are still merely God's creatures, so how could we ever be worthy of having communion with God? Yet He still emptied Himself out to take upon our burden and suffering and eradicate it while divinizing us in the process. The life work of a Christian is to realize how unworthy we are to receive God's blessings, and comparatively, how immense God's love is for us - and as such, how immense our love for our neighbors must be also.
I do think the title should be used carefully (if only because it incidentally lines up with a pagan goddess's title as mentionned in Jeremiah 7:18) but Mary being crowned as queen of the community of saints, and of the whole creation, is not so shocking. First, we are all called to be kings and queens, ruling over God's creation as we are images of Him, the only King. Mary simply got ahead of us on this one because she is the greatest saint. Secondarily though, in the kingdom of Israel, the queen was the king's mother. If Jesus is the king of the world, what does that make Mary?
Vain repetitions like those used in the Psalms? See Psalm 136 for instance. If you read the part where Jesus warns against repetition, you will notice the context of what He says. See:
Pagans prayed with "vain repetitions" because they believed that if they repeated themselves often enough, their gods would finally hear them. The repetitions are vain because they are empty of meaning, and they are wrong because they show that the gods the pagans believed in were not omnipotent and almighty. While praying the Rosary mindlessly is certainly bad (just as any mindless prayer is), the Rosary itself is not "vain repetition" simply because it is not "vain" to begin with, and the repetitions are not to get God to hear us better but to meditate on Him and beg for mercy.
Did you read the Acts of the Apostles?
Nothing is abolished, however we, as Christians, are a spiritual people, and we fulfill the commandments of God not always in the letter, but always in the spirit (that is, the intentions behind the commandments). The Jews may perfectly fulfill the law given to Moses but their heart is hardened, they do not actually become co-workers of God, or extensions of His hand into the world. The law of Moses was given to a specific people in a specific time, and furthermore God knew that until Christ would come noone would be able to fulfill the commandments of God perfectly, which is why the law of Moses is given as a teacher, pedagogy to tell us what God's holiness means and that we must dedicate our entire life to God. The law of Moses is holy, of course, but not the final and perfect appearance of God's will. We, as a people animated by the Holy Spirit, can fulfill God's will, even if it means infringing upon the Mosaic law (because parts became outdated in the economy of salvation, such as honoring the Sabbath or staying away from impurity).
Did you read the epistles of the apostles? They talk about this a lot.
The only silliness would be to not ask questions. Even the prophets asked questions many times. Some were even explicitly angry at God. Jacob got the name of Israel because he fought with God, and as Israel, we too should not be scared to wrestle with God to find answers rather than passively sit back and wait for salvation and wisdom to fall on our lap. Don't feel embarassed about asking questions about Christianity.