The age that is considered elderly medically is age 65 or older.
Elderly when in medical terms is used to describe people 65 years of age and older.
Although this definition of elderly can also be nuanced, and some people use early elderly to refer to people that are between 65 years of age and 74 years of age.
Later elderly is used to describe people over 75 years of age.
Also the concept of "frailty", which is the term used to refer to someone that has decreased physical and mental capacity is also considered when defining a person who is elderly.
If you're at least 65 you're medically considered early elderly.
If over age 65 then you can also be considered late elderly or elderly.
While health decline can vary from person to person, most health decline in people begins gradually and often starts in the 30s or 40s and then accelerates after age 60.
And although some changes such as muscle loss and slower metabolism start earlier, physical decline as well as cognitive changes are more noticeable later in life.
As you age, your skin also becomes sagging and loose and bones lose their mass and muscles also lose their strength.
Most people will begin to notice a shift in the appearance of their face around their 40s and 50s, and some notice a change in their 30s.