I have heard many people joke about been too old to fast or too young to fast. Fasting is not a function of age. Whether you are young or old does not affect your fasting. However, if you have a medical condition why you cannot fast, then you can abstain from corporate fast but don’t just abstain, let the leader or the authority God has placed over you know the reason why you are unable to fast.
Luke 2:37 talks of a widow of about 84 years who chose to serve God in fasting and prayers. Can you imagine that? The woman knew she had no strength to work again but she did not write herself off. She knew that she may not be able to join the sanitation department or the ushering department because of physical strength, but she knew she could still contribute positively to the congregation where she has been planted. That tells me that you have no excuse. You have been planted for a reason and God has a purpose for keeping you alive today. So, don’t give up on yourself and don’t write yourself off.
Like the widow, find your place. You may not be able to do the physical activities, but you may be able to counsel the younger people and mentor them. You may not be able to provide mentorship, but you may be able to baby sit for the younger mothers or run a crèche; no matter who you are and where you are today, you have something to contribute. Even the younger ones, no one is too young to be useful in the house of God. You may not be able to fast till 6 p.m., but you can fast till 3:00 p.m. or 12 noon (for the very young ones). The most important thing is for you to stay connected in the place of prayer.