What is my age?

I was born on 22nd October 1975, is my age calculated from then on or to be calculated from the date and time of conceive, in the womb of my biological mother, when the sperm from the biological father meets the ovary in the womb or the ovary formation date? 

What is the basis of my cell ?

Is it from my biological mom's ovary or from my biological father's womb or it's a combination or it's very unique?

What does our genetic engineering or DNA principle says, time to read some fundamentals on this subject through books?

Any, recommendations?