Maybe you are not aware, but originally to become recognized in association with the International Bible Students baptism was not required. Or, rather, re-baptism. If a person had been previously baptized as a Catholic, Methodist, Baptist, Presbyterian, or whatever, which most of them were, that baptism was considered valid. But, in 1919 that was curtailed. Thereafter a person had to be baptized by someone who was a Bible Student and of course later by Jehovah's Witnesses. It is interesting that apparently the apostles were not baptized. They were only baptized in water by John. Jesus told them they were going to be baptized in fire and spirit, which, of course, they were 10 days after Jesus ascended to heaven. But after the Pentecost outpouring, everyone who accepted Jesus as the Messiah had to be baptized even if they had been baptized by John. So, there seems to be a parallel there with the way the WT handled it before and after 1919.
The 100 questions are important to determine the students' level of knowledge. Baptism is a commitment, even a sacred vow to God. So it is important that the one being baptized knows what is expected.