No, she was not. See 1 Timothy 2:12: “I do not permit a woman to teach or to exercise authority over a man; rather, she is to remain quiet.” Paul supplied two reasons for this prohibition:
“Adam was formed first, then Eve”, meaning that the Lord had designated the man for positions of leadership, not the woman.
“Adam was not deceived, but the woman was deceived and became a transgressor,” and so women through the ages should recoil at putting themselves forward as leaders and/or teachers.
Yet this sister in Thyatira, in defiance of God’s norm as revealed in Scripture, put herself forward as a spokesperson for God and began teaching the saints.
20 But I have this against you, that you tolerate that woman Jezebel, who calls herself a prophetess and is teaching and seducing my servantsto practice sexual immorality and to eat food sacrificed to idols.