According to this blog, Blessed John Robinson was an older man:
BORN at Fernsby, Yorkshire, he lived for some time in the world in the married state, but on becoming a widower he went over to Rheims, was ordained, and sent on the Mission. He was a man of great simplicity and sincerity, and he used to say that " if he could not dispute for the faith as well as some of the others, he could die for it as well as the best." He was apprehended in the very port where he landed, and cast into the Clink prison. His fellow-prisoners, in respect to his age and probity, called him "Father," and he in return styled them his "bairns," and when they were sent off to be executed in different parts of the Kingdom, the good old man lamented for days exceedingly, until at last the warrant for his own execution arrived. To the bearer of the warrant he gave all his money, and on his knees gave God thanks. He was sent to suffer at Ipswich, a long journey taken on foot, but he refused to put on boots, as he said, " These feet of mine have never worn them, and they can well travel now without them, for they will be well repaid."
So like the priests executed at Canterbury and Oxford, Father Robinson had no opportunity to fulfill his mission of serving the Catholics of England--except perhaps in prison and on his way to execution (82 miles from the Clink in Southwark, London!), through his example and his patient endurance.
English Martyrs of October 1, 1588, pray for us.