Haha, Bob Ross of bonsai is a good comparison! He knows what he's doing by the way, I have seen some of his videos on that channel.
Your approach could work, however it is not the fastest way to get a nice bonsai tree. I mean you can keep the tree small from the beginning (like you do now), but it would take decades this way before the stem would be impressive in thickness and would look like a real small tree. This is because the container keeps the plant small (no room for roots, so no optimal resources to grow). A trick what most bonsai growers do (Peter Chang included), is to let the seedling first grow for 5 or so years in larger containers. They will have plenty of room for their roots and grow thick stems this way. They will also grow in length, but that is something you'll have to prune later on. The larger the plant gets, the faster it will grow. Then, after 5 years, prune them into bonsai and put them in your nice bonsai pot. The stem is then impressive already and give it a few more years of shaping and pruning, and it will look like a miniature tree.
Another trick is to choose a species that has not so large leaves, because the smaller they are the more they are in the right proportion with the small tree. Don't understand me wrong, in principle every tree can be used for bonsai, but the larger the leaves the more difficult it is, and your Acer pseudoplatanus (in your bonsai pot) is one of the most difficult ones to bonsai. I mean it is very hard to get these leaves in the right proportion. The leaves are very difficult to get smaller.
Don't let me dis-encourage you, a nice thing with bonsai is that you will learn to be more patient...