Conditions of will

Dear Experts:

Is there any age requirements to write a will for my properties. I heard that one should reach 50 years to be eligible to write will otherwise which is void if some one write below age 50 years.

My age is 35 years and am I eligible to write a will for my self aquired property? Should I have any serious health problems to write a will or am I eligible to write it if am in a state of good health?

Kindly clarify

karan