Dear Maureen, 

It is always the right time to start discerning, because by discerning we usually mean looking into, asking ourselves what God wants us to do. So it is always good to ask that question. What is a little more difficult to tell is when you have gotten an answer, what it actually is, and if now is the right time to act on it.

It is OK at any age to ask if God is calling you to give your life to him. You can ask the question even if there is no possibility of you doing it right away, and there is no urgency to it. It is always good to get help from someone if you can when you are discerning. If you are at a stage in which you can take a step, then it is especially important to ask yourself the question and look for an answer. It is very normal to have wide swings when we are discerning a vocation, because we often go on our feelings and so, one day we feel there is nothing we would like more than to be a priest or nun, the next day all we want is a family, and maybe the day after we don't even feel like taking on the responsibility of a family and just want to be free and have a good time. That's why even though we tend to make discernment a thing of our feelings, we really need and ought to go much deeper than that. We have to make sure our discernment consists in an honest attempt to get all the hints that God is giving me about what HE would like me to do with my life, how I fit into his plan to bring as many people as possible to the happiness of knowing him in this life and possessing him in heaven.

As to the answer you get, it will never be mathematically absolute. Even when all the correct signs for a vocation are there, there will always be some uncertainty until you try it and have it confirmed by someone who speaks for the Church in accepting you and validating your vocation (Bishop, religious superior). And they can't accept you until they get to know you and see how you do when you try to follow it. So, once you discern you have to be ready to take the plunge.

God bless,