Deep down, Ty knew his mother was right. Somehow he could tell this was who he wanted to be, and WHAT he wanted to be. His life as a human had almost always been miserable, and he could sense that this was a chance for a better life. He followed her up the path to the top, though she kept going.
He realized why a moment later, as the pale green light that had enveloped her covered him. His clothes vanished, and he felt things he'd never experienced before as his body began to change. Before his eyes he seemed to turn slightly more curvaceous, his skin softer, his hair longer, his muscles more petite. His nipples perked up and turned larger, and soft flesh swelled on his chest as he developed breasts. By this point Ty felt less tightly connected to the idea of being a boy- becoming a nymph felt so nice he realized giving it up wasn't so bad.
He groaned and ejaculated, his seed flowing into a river that ran down the side of the path- it was kept alive there and would soon impregnate nymphs that swam in the water. Ty's balls were soon emptied, and the nymph world finally castrated him. His balls moved up inside him and started to change into her ovaries, his scrotum sank inwards and transformed into a feminine mound, and his penis shrank rapidly until it formed a clitoral nub.
As the light faded, she realized she had fully become a nymph again, and loved how it felt. She started to follow her mom again...