Everything has a purpose. The kit lens(es) are able to do things that the 50/f1.7 can not do. The 50 too, is somewhat single purpose in its fixed focal length, and is able to perform at a much higher level than the kit lens. So, a lot of the experience you need to gain, is how to apply the tools that you have, and even in a pinch, use what you have to fulfill the task at hand. Photography is at best an exercise in compromises.
Also, its very difficult to be a generalist - being good at everything (and having the equipment to support everything). It might be better to at least start out with some sort of focus in an area in photography that appeals to you. As you gain experience and understanding, along with the ability to solve various technical problems with your current set of tools, you will develop an understanding of where you need additional equipment support.
Just remember, you can go broke very quickly in photography buying everything that you think you need.