When I talk about my kids, I put their age behind it... DS8, DD6....this way anyone reading my posts know my kids age.....
I don't use it to display what order my child was born in... DS1 (dear first born son), etc.....
JMHO 
I finally figured out fellow Mums, and their acronyms... I wonder if they figured out mine! lol...
I don't have 8, children.....
ps...your way is confusing...as when I read it, I presume your child is ONE years old... Not your "first born".... 