Do you want to learn engraving? If so then it's simple. . As long as the handwriting is good, it will be fine
If you are studying sculpture, such as Shoushan stone carving, stone carving/jade carving. Clay sculptures and the like are difficult. Because this requires art skills.
Go to art school first and learn sketching. Most art schools have sculpture classes. Sculpture class sketching is the most demanding!
I graduated from a sculpture school, so I find it very difficult. . . Maybe my understanding is not good. I don’t know how you are?