Why My Hair Line is Receding ??

Genetics

There can't be one reason for your receding hairline.
The three major cause of hair fall are:
you are not taking enough nutrition in your diet
Not having enough sleep
Taking stress
first try to complete your diet, sleep well, and exercise daily . If this doesn't work too then you can meet any dermatologist for your problem.

If it is increasing fastly then must consult a dermatologist or utilize home remedies for permanent results of hair loss treatment.

It can be many reason, the main reason of hair fall is stress, lifestyle and diet. So you should to care on your diet and avoid from stress

Bad eating habit or it could be because of genetics too.

The most common cause of hair loss is a hereditary condition called male-pattern baldness or female-pattern baldness. It usually occurs gradually with aging and in predictable patterns — a receding hairline and bald spots in men and thinning hair in women. Hormonal changes and medical conditions.