Your RCIA instructor is correct. Making a profound bow during the profession of faith at the words “by the power of the Holy Spirit he was born of the Virgin Mary and became man” is part of the rubrics and should be followed. Perhaps you can approach your priest privately with your concern. I’m sure he’ll be willing to take the necessary steps to correct the problem.
The *General Instruction of the Roman Missal * no. 234 instructs the faithful to make a “profound bow” (from the waist) within the profession of faith at the words “by the power of the Holy Spirit”.
234. There are two kinds of bow, a bow of the head and a bow of the body:
a. A bow of the head is made when the three divine Persons are named together and at the name of Jesus, Mary and the saint in whose honor Mass is celebrated.
b. A bow of the body, or profound bow, is made: toward the altar if there is no tabernacle with the blessed sacrament; during the prayers, <Almighty God, cleanse> and <Lord God, we ask you to receive>; within the profession of faith at the words, ; in Eucharistic Prayer I (Roman Canon) at the words, <Almighty God, we pray>. The same kind of bow is made by the deacon when he asks the blessing before the gospel. In addition, the priest bends over slightly as he says the words of the Lord at the consecration.”
The USCCB explains what this bow signifies:
“In the Creed we are invited to bow at the words which commemorate the Incarnation: by the power of the Holy Spirit he was born of the Virgin Mary and became man. This gesture signifies our profound respect and gratitude to Christ who, though God, did not hesitate to come among us as a human being, sharing our human condition in order to save us from sin and restore us to friendship with God. This gratitude is expressed with even greater solemnity on the Feast of the Annunciation of the Lord and on Christmas when we genuflect at these words.”
Click here for clarifications issued by the Sacred Congregation for Sacraments and Divine Worship (Notitiae) concerning this particular act of reverence.