Welcome Momagain ! you have landed in a wonderful pool of early learning
For your query on "What age do you start? " , I go with skylark ..the learning begins right in the prenatal stage ! And hatsoff in your case , ur kid is gifted to have a wonderful mom !
0 to 2 months pretty much smiles and songs would do great ! just narrate him what all u do..like 'mommy is changing ur diapers'...'its sunny and bright today' etc . Try out the black n white patterns from Brillkids infant section ..I used to stick them near his cribs . And little toys of black n white to hold n see. (coz their eye sight is not fully developed yet )
3 to 4 months u can introduce to contrast Red patterns , do sleep talk n alpha music for relaxation.
and ofcourse just read to ur little one....i was even read aloud the parenting book for that matter..
And action songs with expressions...they would enjoy n love it !
Anywhere from 3 to 6 months would be a good time to introduce flash cards - u can print it out from brill kids. Do more of touch n feel learn, make him feel the soft,mushy,slithery,ridgy, shiny stuffs
they wud love it.
Happy mommying
-cheerymom