In a national study of Protestant churches done in 1990, Peter Benson and Carolyn Eklin surveyed hundreds of people and distilled seven characteristics of a mature faith. You may not agree with everything on their list, but it's still instructive to look at their conclusions.
1. Trusts in God's saving grace and believes firmly in the humanity and divinity of Jesus.
2. Experiences a sense of personal well-being, security, and peace.
3. Integrates faith and life, seeing work, family, social relationships, and political choices as part of one's religious life.
4. Seeks spiritual growth through study, reflection, prayer, discussion with others.
5. Seeks to be part of a community of believers who give witness to their faith and support and nourish one another.
6. Holds life-affirming values, including commitment to racial and gender equality, affirmation of cultural diversity, and a personal sense of responsibility for the welfare of others.
7. Serves humanity, consistently and passionately, through acts of love and justice.