The Second Vatican Council (1962-65) called for the renewal of Lent, recovering its ancient baptismal character. This recovery was significantly advanced by the restoration of the catechumenate mandated by the Rite of Christian Initiation of Adults (1972). As Catholics have increasingly interacted with catechumens in the final stage of their preparation for Baptism, they have begun to understand Lent as a season of baptismal preparation and baptismal renewal.
Since Ash Wednesday marks the beginning of Lent, it naturally is also beginning to recover a baptismal focus. One hint of this is the second formula that is offered for the imposition of ashes: "Turn away from sin and be faithful to the gospel." Though it doesn't explicitly mention Baptism, it recalls our baptismal promises to reject sin and profess our faith. It is a clear call to conversion, to that movement away from sin and toward Christ that we have to embrace over and over again through our lives.
As the beginning of Lent, Ash Wednesday calls us to the conversion journey that marks the season. As the catechumens enter the final stage of their preparation for the Easter sacraments, we are all called to walk with them so that we will be prepared to renew our baptismal promises when Easter arrives.