Shipped = available on the web or app store (or whatever) — its when the product is accessible to others
It’s hard to advance your design skills if you don’t move beyond mockups. During the coding/shipping process, a lot of things pop up (i.e. empty states, error states, conditional screens/interactions, logic/what if questions, etc.) that you normally wouldn’t consider as a new designer. Only by going through the end-to-end design process, and shipping your design will you be able to grasp some of these concepts. Hope that helps!