A:
Acts of the Apostles contains a brief account of Stephen being appointed a deacon of the early church and of his subsequent martyrdom, but does not tell how old he was. Raymond E. Brown (An Introduction to the New Testament) says that we can never verify the martyrdom or even existence of Stephen, in whcih case it is a moot point how old he was.
No, Saint Monica was not a martyr. She is known for her piety and devotion in the Christian faith, particularly for her prayers and influence on her son, Saint Augustine, who later became a prominent theologian and saint. Monica is recognized as a model of perseverance and faith.
Saint Patrick died of natural causes, probably complications of old age. He was not a martyr.
Monica probably died of complications of old age. She was not a martyr but lived a martyr's life.
No, St. Augustine died of natural causes, probably due to old age.
No, Saint Juan Diego was not a martyr. He is known for his vision of the Virgin Mary, which led to the construction of the Basilica of Our Lady of Guadalupe in Mexico City.
Saint Adam is not recognized as a martyr in Christian tradition. He is sometimes referred to as the patron saint of gardeners.
Saint Patrick wasn't actually killed, latest researches say that he rather died from a various disease or from natural death.
We do not know when, where or how Luke died. Most resources say he died of natural causes (old age?) and yet ither say he died a martyr's death.
That was Jacinta Marto, one of the girls who witnessed the miracle of our Lady of Fatima. She died of sickness when she was only 10 years old.
Stephen was thought to have been a fairly young man when he died. However, we do not have a precise age.His age at death was unknown but he was apparently quite young, either in his 20s or 30s.
St. Patrick is not venerated as a martyr, so it is not correct to assert that he was killed. He is assumed to have died a natural death. He is venerated as the apostle of Ireland because he was instrumental in spreading the Christian faith there.
Saint Bernadette of Lourdes was 35 years old when she died.