TinkerCAD is easy to get started with and is a fine starting point. If you want to go farther than TinkerCAD can reasonably take you, I’ve done a lot of modeling in onshape (after using Fusion360 for a few years). Parametric CAD systems (Fusion, onshape, solidworks, freeCAD) feel like a nice intersection of design and programming to me.

My current workflow is onshape for all modeling (because it has excellent multi-player concurrently editing support, relevant to FRC robotics), then Fusion for CAM¹ if it’s going to CNC equipment. Onshape added support for CAM in the last 8 months, but I haven’t switched yet.

¹ - Computer Aided Manufacturing-turn a shape into a series of instructions for the CNC equipment. Roughly:

CAM : CNC :: slicer : 3D printer