Should a person learn to sew by hand before trying to sew with a machine?”
Learn both together, if you have access to a sewing machine. Though it’s possible to construct an entire project by hand, the machine will speed up the process immensely! (for example, if clothing were sewn completely by hand, we’d all probably have to make our own because very few people could afford to pay the labor!) It’s possible to sew some things completely with a machine, and no hand sewing. Many non-clothing projects can be made without any hand sewing (bags, cushions, window treatments). The best quality clothes have some hand sewing for finishing and details (hems, buttons, zips, some trims).