The Council of Trent was held in the mid 1500s, to refute the errors of Protestantism and to concisely set forth Catholic beliefs. Among the topics discussed were the Sacraments, including Baptism. The participants in this council aimed to eradicate erroneous teachings and practices regarding the Sacraments and they were quite specific in doing so. It was a dogmatic council and the proceedings are binding upon the Church.
In order to promulgate the council, a catechism was written immediately afterwards. Pope Saint Pius V and Saint Charles Borromeo were both heavily involved in that undertaking. The canons and decrees of the Council of Trent and the Catechism of the Council of Trent can be obtained from Tan Publishing. In this day and age of dodgy catechesis, I highly recommend that everyone obtain copies.
Meanwhile, here is what the Catechism of the Council of Trent says of Baptism. Particular germane to the topic of the "I versus we" discussion is the section under "words of the form". Yes, it really does matter what word is used. Specific words convey specific meanings. The Church has always understood that. It's high time that some Catholics start appreciating that reality.
