Your baby starts her journey into adulthood with very little going for her other than an inborn potential to grow and become. Within the first few weeks of life, she begins the lifelong process of experiencing, exploring, and expressing herself. This is a very physical/doing time of life for baby. She spends most of her waking hours looking, making noises, learning to hold up her head and turn over, squirming and moving around, trying and then learning to pick things up, usually putting them in her mouth, and gradually organizing her life around the major goals of getting to things and getting into them. As your baby becomes a toddler (around the age of eighteen months), the circle of her world starts to expand. There are myriad things to get into and to learn to stay out of, to climb on and around, to explore and experiment with, to take apart and throw around. There is a long list of things to do, such as learning to talk, to use the bathroom, and to feed herself, figuring out new ways to get others to pay attention, finding out about rules and restrictions, getting better at moving around without falling down - generally discovering the physical world.
As your toddler becomes a preschooler, her world continues to expand geometrically with things to do or to avoid, experiences to have or to refrain from, with more complicated toys, more elaborate opportunities, and with those ever-present but changing rules and restrictions. The world of puzzles and coloring books, bicycles and roller skates, games and good manners also begins to come into focus.
As your preschooler becomes a grade schooler, the circle of her world expands yet further and rules and restrictions begin to decrease, even if only slightly. Not only is she able to do more things, but she is allowed to, even encouraged to do more. Somewhat suddenly, it may seem to your grade schooler, you and other adults expect her to learn how to do things that are sometimes difficult or tedious. Fun and work are becoming interacting and interrelated parts of life.
As your grade schooler moves into adolescence, the circle of her life continues to expand, and the rules and restrictions change and lessen. Your child by then has developed a fairly well-established pattern of discovery, experimentation, and mastery; she has developed an amazingly complex array of skills, abilities, and behaviors to be consciously used or not, depending on the circumstances. And still more skills and behaviors are yet to be learned - how to participate in team sports and group activities, what is the proper behavior in a multitude of situations, how to do geometry, how to drive a car, how to behave on dates and in other social situations. Gradually, the developing individual comes to do and act less like your child and more like an adult.