I think this is an amazing dream. It sounds like there may be some wistfulness to the dream--like a wish for another child, a baby girl. And while that might be one interpretation--a wish fulfillment dream--I think the another interpretation is probably more likely and is, to me, far more positive and exciting--even if it doesn't sound like it.
I think that that dream was a dream of the archetype of the "Divine Child." Here's a link to a website that has great succinct definitions of pretty much all the major Jungian archetypes:
Myths-Dreams-Symbols To quote that site: "The Divine Child is the archetype of the regenerative force that leads us toward wholeness. 'Becoming as a little child' as expressed in the Gospels. It is a symbol of the true self, of the totality of our being, as opposed to the limited and limiting ego."
I think that is what your child in your dream was representing and I think it is the reason it made such an impression on you. Jung called these dreams the "Great Dreams"--dreams that hit a high spiritual note and resonate in our souls. I think that what you were seeing was you--you yourself in your wonderful innocent pure soul state! This is also underscored by the child's eye--blue. Blue is often associated with spiritual matters, heaven, and is a color often associated with Mary.
I had a Divine Child dream once and like yours, mine has stuck with me forever. Sometimes I just think about it to get that happy feeling you wrote about!
Treasure that dream!