Feel your age
Definition 1 of 2
Pro Tip 1/3Physical Exhaustion
Used when feeling physically worn out, highlighting the impact of age on stamina. 
After playing football with the kids, I could really feel my age.
Pro Tip 2/3Emotional Tone
Often conveys a wistful or resigned feeling regarding one's limitations. 
Looking at all the young dancers, I started to feel my age.
Pro Tip 3/3Cultural Nuance
May imply respect for the elderly or signify wisdom in certain cultures. 
In my village, when you begin to feel your age, you're regarded as an elder.