Building a building involves knowing how much material of various sorts is needed, how much it will cost and being able to judge whether the final structure as envisaged will stand up well to the numerous stresses of internal loading, temperature variations, high winds, earthquake shock waves, etc to which it will be exposed . And if the structure, as you indicate, is a skyscraper, all of these factors will loom large. You need to be able to calculate material quantities, internal load stresses, the resonant responses of the structure to shock waves, its flexure response to high winds, and so on. Undoubtedly, maths is involved, and for some of the factors, quite a lot of it. Why not start more modestly, say with building a garden shed?