Our youth has questions

Yes, as Catholics we must attend Sunday Mass, if we don't attend it is considered a mortal sin.

“Do not think”, says Jesus in the Sermon on the Mount, “that I have come to abolish the law and the prophets; I have come not to abolish them but to fulfil them” (Mt 5,17). (1965–1972, 1977, 1983–1985) Jesus, being a faithful Jew, lived according to the ethical ideas and requirements of his time. But on a series of issues he departed from a literal, merely formal interpretation of the Law.

Mary was totally responsive and open to God (Lk 1:38). Thus she was able to become the “Mother of God” through the working of the Holy Spirit—and as Christ’s Mother to become also the Mother of Christians, indeed, the Mother of all mankind. 721–726 Mary made it possible for the Holy Spirit to work the miracle of all miracles: the Incarnation of God.

Fifty days after his Resurrection, the Lord sent the Holy Spirit down from heaven upon his disciples. The age of the began. 731–733 On Pentecost the Holy Spirit transformed fearful apostles into courageous witnesses to Christ. In a very short time, thousands had themselves baptized: it was the birthday of the Church. The miracle of the languages on shows that the Church is there for all peoples from the very beginning: She is universal (= the Latin term for the Greek kat’ holon, catholic) and missionary. She speaks to all men, overcomes ethnic and linguistic barriers, and can be understood by all. To this day the Holy Spirit is the “soul” of the Church, the essential principle of her life.