Is it required that I take vows in front of a congregation to become a member?

Yes, The United Methodist Church does expect that people who seek to unite with The United Methodist Church will profess their faith before the congregation. Membership is a relationship with other Christians who are United Methodists. Sometimes we think of membership as having one’s name on the roll of the church. The United Methodist Church does have membership rolls, but the roll is simply a listing of those who have committed themselves to relationship with one another for the sake of the ministry and mission of Jesus Christ and for mutual oversight and care. This understanding should be clear from the citations given below:

Paragraph 217 in the 2004 Book of Discipline reads:

When persons unite as professing members with a local United Methodist church, they profess their faith in God, the Father Almighty, maker of heaven and earth; in Jesus Christ his only Son, and in the Holy Spirit. Thus, they make known their desire to live their daily lives as disciples of Jesus Christ. They covenant together with God and with the members of the local church to keep the vows which are a part of the order of confirmation and reception into the Church....(From The Book of Discipline of The United Methodist Church — 2004. Copyright © 2004 by The United Methodist Publishing House. Used by permission.)

Further, Paragraph 219 on “Mutual Responsibility” emphasizes the covenantal and relational nature of membership and discipleship:

Faithful discipleship includes the obligation to participate in the corporate life of the congregation with fellow members of the body of Christ. A member is bound in sacred covenant to shoulder the burdens, share the risks, and celebrate the joys of fellow members. A Christian is called to speak the truth in love, always ready to confront conflict in the spirit of forgiveness and reconciliation.
(From The Book of Discipline of The United Methodist Church — 2004. Copyright © 2004 by The United Methodist Publishing House. Used by permission.)

The italicized material cited above makes it clear that one who is a member has to be in relationship with the other members of the church.

Paragraph 224 on receiving members “Outside of Congregational Settings” states:

Any candidate for church membership who for good reason is unable to appear before the congregation may, at the discretion of the pastor, be received elsewhere in accordance with the Ritual of The United Methodist Church. In any such case lay members should be present to represent the congregation. Names of such persons shall be placed on the church roll, and announcement of their reception shall be made to the congregation.
(From The Book of Discipline of The United Methodist Church — 2004. Copyright © 2004 by The United Methodist Publishing House. Used by permission.)

Clearly, this paragraph recognizes that there may be exceptions to the rule, without specifying what the criteria for “good reason” is. This paragraph allows for pastoral discretion and provides for representation of the congregation in a home, hospital, or other place.