What is the best age for a person to have their first born???

I'd say late 20s early 30s maybe. At those ages you've usually got your life stabilized.

Umm...I guess when you're mentally mature enough.
Like the middle oder late 20's.
There's no need to rush, parenting is hard.

i think when people are in their 30s.i would like to have my first baby when i turn 30 and up.because than i will have a good job,and be mature to create a family :)