Was Alma the first Book of Mormon prophet to baptize?

The "Tvilah" is the act of immersion in natural sourced water, called a "Mikvah". In the Jewish Bible and other Jewish texts, immersion in water for ritual purification was established for restoration to a condition of "ritual purity" in specific circumstances. For example, Jews who (according to the Law of Moses) became ritually defiled by contact with a corpse had to use the mikvah before being allowed to participate in the Holy Temple. Immersion is required for converts to Judaism as part of their conversion.

• The water source has to be natural or "living Water".
  
• It is done naked.
  

"And now, if the Lamb of God, he being holy, should have need to be baptized by water, to fulfil all righteousness, O then, how much more need have we, being unholy, to be baptized, yea, even by water!" - 2Ne. 31:5

Therefore, he took Moses out of their midst, and the Holy Priesthood also;
And the lesser priesthood continued, which priesthood holdeth the key of the ministering of angels and the preparatory gospel;
Which gospel is the gospel of repentance and of baptism, and the remission of sins, and the law of fcarnal commandments, which the Lord in his wrath caused to continue with the house of Aaron among the children of Israel until John, whom God raised up, being filled with the Holy Ghost from his mother's womb." - D&C 84:25-27