Hi, Michele,
I love all the great advice I've gotten on this board, and one piece of advice that seems to be consistent is: Don't push too hard when they're young. Enjoy them. Cuddle them. Read to them. If the time of day you are focusing on extra educational things is rough, then they're going to associate 'aftershooling' with that emotional state. You want it to be a good thing, so keep it positive and enjoyable.
They'll be able to handle more work-type activities as they get older. But their emotional approach to learning will inevitably hinge on your attitudes and how they feel when they're with you. So . . . everybody, have fun!
Read fairy tales, read bible stories, read simple science picture books. Plant beans, blow bubbles, see what floats & what sinks, sing folk songs, sing skip counting songs, dance Skip To My Lou.
HTH