Would children have worn corsets in the 18th century?
Yes. At that time they were called “stays” and were universally recommended to help children grow to a good shape and posture. The first link shows a surviving original pair of stays. These, being stitched out of linen and whalebone, would have been quite a posh garment. Cheap stays, such as those issued to charity children, were made of leather. Children of different ages wore different cloths, Children under 7 – both girls and boys – wore dresses, which were back-fastening unlike adult women’s dresses which fastened at the front. They would also have worn aprons, and often caps to keep their heads warm. Very small children often wore a cap made out of padded rolls, called a “pudding cap”, to protect their heads from falls and bumps. The third link gives a more detailed description of the kind of clothes worn.