25 Moreover, if you ask how it is that a mere infant which has never sinned is seized by the devil, or at what age we shall rise again seeing that we die at different ages; my only answer— an unwelcome one, I fancy— will be in the words of scripture: “The judgments of God are a great deep,” and “O the depth of the riches both of the wisdom and knowledge of God! How unsearchable are his judgments, and his ways past finding out! For who has known the mind of the Lord?
Or who has been his counsellor?” No difference of age can affect the reality of the body. Although our frames are in a perpetual flux and lose or gain daily, these changes do not make us different individuals. I was not one person at ten years old, another at thirty and another at fifty; nor am I another now when all my head is gray. According to the traditions of the church and the teaching of the apostle Paul, the answer must be this; that we shall rise as perfect men in the measure of the stature of the fullness of Christ. At this age the Jews suppose Adam to have been created and at this age we read that the Lord and Saviour rose again. Many other arguments did I adduce from both testaments to stifle the outcry of this heretic.
Source: Letters (New Advent)