"a lovely indoor tree"
I think you have a mistake in your idea of bonsai. Typicvally, you grow bonsai outside. Indoors the conditions are just not good enough to develop trees to the level that they can become a bonsai. That being said, some people are willing to spend their life savings on climate systems and manage to create the right environment, but that is really a step too far for most people starting out.
Start off with plants that grow well in your climate. Once you get the hang of growing bonsai you can consider growing indoors.