I started my grand children with pillow case. A quick project that they can use immediately.
Then we did pj's. Simple pull on pants and over the head top. Or just the pants teamed up with a matching color T-shirt.
They are proud to wear them and it doesnt matter how straight seams are.
For quilting, the first project was simple squares 6 1/2" sewed together (I did the cutting). Chose 2 or 3 colors, one a novelity print that they pick out. They made a lap quilt to use while watching TV. Tie the quilt. It is much more forgiving for uneven seams, and use a puffy batting rather than a flat one like warm and natural. Hides the fact that the squares may not be flat.