Who invented Sewing?
When people first began to wear clothing, about 60,000 years ago, they didn't sew it at all: they just wrapped leather or furs around themselves. Probably they soon began to tie their clothes on with string or leather cords. People continued to wrap their leggings on this way well into modern times.
But about 45,000 BC, when people first began living in Central Asia, where it was colder, they wanted warmer, stronger clothing, and they began to use sharp pointed sticks or stone tools called awls to poke holes in their clothes so they could run the cords through the clothes instead of just around them. They used the awls to poke the end of the cord through the holes, too. Both Neanderthals and modern people used awls this way.
Sewing with an awl
Then maybe around 40,000 BC, still in Central Asia, somebody had the idea to make a hole in the end of the awl and thread the first needle. This made sewing a lot faster and easier, and soon the new idea spread to other cold places like northern Europe. These early needles were made of bone and ivory, like awls.
Around 9000 BC, people in West Asia began to spin thread out of wool or linen and weave cloth out of it. It was much easier to sew cloth than to sew leather, so people began to do more sewing. When people began to use bronze, about 3000 BC, they quickly started to make sharper, lighter needles out of bronze.
It took so long to spin and weave a piece of cloth, that people generally didn't want to cut the cloth up: it was too valuable. Most people wore the whole piece of cloth, wrapped around them as a sari or a shawl or a cloak or a toga. But in Central Asia, where people rode horses, they sewed their cloth into pants. It was cold, too, so they sewed thick quilted jackets and coats.
You Can Weave!: Projects for Young Weavers, by Kathleen Monaghan (2001).
World Textiles: A Concise History, by Mary Schoeser (2003). For adults.
Women's Work: The First 20,000 Years : Women, Cloth, and Society in Early Times, by Elizabeth Wayland Barber (1995). Not for kids, but an interested high schooler could read it. Fascinating ideas about the way people made cloth in ancient times, and why it was that way.