Discerning a vocation to be baptised is a personal and often very private process and not disclosed publicly - God calls us sometimes when we are young or maybe later in life.
So when should people start answering God’s call?
From a general point of view, the answer would be, “Right away”, meaning as soon as you hear the call and prudently come to the conclusion that it may be authentic you should act on it.
In our daily life, whenever God asks us to do something, we should follow through quickly and generously. That is the general principal, but when we are faced with a concrete individual, several factors and circumstances can affect the answer. For someone still underage their parents’ desires are a major factor in their decision and their permission is needed to take any definitive step.
Help and support are available in most parishes through RCIA which is a faith exploration and sharing group, including catechists and parishioners which meets on a regular basis, usually weekly, to support and inform interested youth and adult “enquirers”. Anyone is welcome to come to these sessions without making any sort of commitment.
All in all, the important attitude for any young person or adult to foster is generosity with God. Just like Samuel in the Bible (1 Samuel 3): “Speak, Lord, for your servant is listening!”