I don't remember this stage of my life very much, but I know that I was considered a fetus between the 8th week of my gestation to birth. During this stage I was developing my teeth and all of my organs, growing into my cramped living space.
At this stage my lungs have just developed into being viable, and my experience of the world around me is mostly sensory and not remembered. My mom tells me I was a happy baby and one of the only times I cried badly was at my actual birth.
At this stage in life, earnest brain development is occurring and I am beginning to develop my self-concept and the ability to have conscious memory. I, personally, went through an extremely obnoxious babbling stage at this point in my life.
Physics development almost finishes during this stage and while the brain continues to develop, the frontal lobe/ decision-making center lags behind other areas of the brain. Obviously
During this stage it becomes harder to recall information and there is a noticeable decline in fluid intelligence, or the ability to solve new types of problems. Hopefully I won't be the kind of old person that is stuck in their ways and unhappy with all the changes that will occur around me.