>78 years old
>Still plays shows
I think hell be fine

The brain seems to be the longest lasting organ in your body.

Everything else goes to shit pretty fast, so of course your appearance noticeably went to shit. Humans hit their peak early in life, early 20s, and it's only a decline thereafter. Women hit the wall at 30. Men start balding either in their teens or 20s.
Muscle mass starts decreasing in your 30s. Bones start losing density. Reflexes start to go. But your mental abilities remain sharp and focused all the way into old age.