There is no age limit to being named a saint.
Saint Peter died and entered Heaven as a saint when he was about 65 years old.
Lucy was martyred at the age of 21 and became a saint at that time.
No, Saint Dominic Savio did not become a priest. He was a student of Saint John Bosco and aspired to become a priest, but he died at a young age before he could be ordained. He is known for his piety and devotion to God.
Anne did not become a saint until she died at a VERY old age.
Saint Brigid or Bride died when she was 70 and got to meet Saint Patrick and Saint Brendan.
Saint Rafqa, also known as Saint Rebecca, died on March 23, 1914, at the age of 82.
Brigid had stopped aging when she became a saint as she had died. Being dead is the first requirement for being declared a saint.
Cameron, who died as a martyr at three years of age in Sardinia, is not a patron saint.
Saint Dominic Savio was known for his exceptional piety and dedication to living a holy life from a young age. He demonstrated a deep love for God and tirelessly strived to live a life of virtue. His strong faith, purity of heart, and devotion to the Christian faith inspired others, leading to his canonization as a saint.
Saint Dymphna would be the saint's name you are looking for.
I can find no reference to any saint by the name of Naomi.