My question expressions are not about natural and common expressions of asking and telling about a person's age, nor are they necessarily meant to be replies to such (spoken) interrogatives as "How old are you?", "What is your age?", etc. They can also be personal introductory statements, such as in "Am i fat? My height is 172.5cm, i weigh 70.5kg and my age is 14." and "Hi, my age is 33, my height is 5.11 ft. & my weight is around 114 kgs. How can i reduce it at the earliest?"
Which of my question expressions have you, my dear speakers of North American and British English, heard and/or read and accepted as correct/standard? I personally prefer "My age is six years." ("My age is N." is ok in most occasions.)