Once you're confident working in two dimensions, you might want to jump into the third one!
If you're completely new to 3D, there's no need to spend lots of money on expensive software. We recommend both
Blender and
Spline.
They're both
free 3D programmes that will give you amazing results. For work for web Spline is perfect, and for a more cinematic finish and in-depth options Blender is the one.