We hope you're here because of a good conversation you've had with someone about either becoming Catholic or reconnecting with your Catholic Faith.
If you've been away from the Church but are already fully initiated into the Catholic Church by receiving the sacraments of Baptism, Confirmation, and The Holy Eucharist, you'll probably need to meet with the priest to talk about your journey and discern the best way forward.
Often, those who have been away from the Church have spent some time in another Christian ecclesial community. It's possible you've received some formation in those communities that are contrary to what Catholics believe.
After going through The Creed in a period of prayer and reflection (with the priest, a member of the parish trained to assist with this process, or within the Order of Christian Initiation courses known as the RCIA) you'll be invited to go to Sacramental Reconciliation (Confession) and then make your Profession of Faith–reciting the Creed that you've studied and can now take up as your own!
The process length varies from person to person, because coming back into practicing the Faith isn't just a calendar oriented event, but rather a time of formation. Ordinarily, the RCIA takes place over the course of a year, culminating with being received into full communion at the Mass of The Solemn Easter Vigil. But, the priest will be happy to help with assessing where you are in your journey back to the Catholic Chuch and possibly suggest an alternate timeframe.