How old will you be in heaven/hell?

The change in appearance and outer features as one ages are related to this world, but this isn’t the case for the hereafter, especially heaven; people don’t have different appearances and faces there. For example, it is not so that some will be children, some will be middle aged, and some old. Even if we believe that the world to come is a material one, still, age, the way we see and perceive it in this world, will not be a factor. What can be concluded from narrations in this regard, is that those entering Paradise will be young and beautiful:

يدخلون الجنة شبابا منورين و قال إن أهل الجنة جرد مرد مکحلون 1
Those entering Paradise will enter as young illuminating beautiful youth.

In put it in other terms, they will always be in the best form and state, this joy not being hindered the least by the passing of time.

In the Quran, when it speaks of the pure heavenly spouses, it says that those in heaven will have spouses who only look to their husbands and are of like age and young:

2 {وَ عِنْدَهُمْ قاصِراتُ الطَّرْفِ أَتْرابٌ}
With companions of modest look, the same in age, by their side.

In this verse, atrāb means being of the same age and is one of the attributes of heavenly women in respect to their husbands; being of the same age increases attractiveness among couples. Atrāb can also be an attribute of the women among themselves, in other words, the verse can also mean that all the women therein have the same age. 3 None of these women will be subject to old age; they are neither children nor old and feeble. 4

[1] Ibn Shahr Ashub, Manaqib Aal Abi Talib, vol. 1, p. 148, Allamah Publications Press, Qum, 2000.
[2] Quran, Surah Sad. 52
[3] Makarem Shirazi, Tafsir Nemouneh, vol. 19, p. 317, Daar al-Kutub al-Islamiyyah, Tehran, first edition, 1995; Suyuti, Jalal al-Din, al-Durr al-Manthur fi Tafsir al-Ma’thur, vol. 5, p. 318, Ayatullah Mar’ashi Najafi Library, Qum, 1404 AH.
[4] Ibn Ajibah, Ahmad bin Muhammad, al-Bahr al-Madid fi Tafsir al-Quran al-Majid, researched by Qurashi Raslan, Ahmad Abdullah, vol. 5, p. 36, Published by Zaki, Hasan Abbas, Cairo, 1419 AH; Tafsir al-Saafi, Fayd Kashani, Mulla Muhsin, Tafsir al-Saafi, researched by A’lami, Husein, vol. 4, p. 306, al-Sadr Press, second edition, Tehran, 1415 AH.