I recently heard a sermon in which the preacher gave statistics of the probability of someone’s being saved at different ages, and for those of us who pray for prodigals that are over the age of 18, the statistics were very disheartening.
However, our prayers overcome statistics, making them of no consequence, because God is no respecter of persons and can save the older as well as the younger. (See Acts 10:35 and 2 Peter 3:9.) The prodigals we are seeing saved in our local congregation are all ages. One man was 51. Another has several grandchildren. Several were in their 40s, and one was in his 70s. There is no limit to what God can do.
So keep praying. Jesus came to seek and to save the lost, no matter their ages. (See Luke 19:10).