I found a nursery/bonsai learning center in my area so I plan to stop by there to see if they have any suggestions as well, since they are in the same climate that I am.
This is an excellent idea, especially if they have some sort of classes that you can take.
I know that I need to replace the soil because what I have now is very fine and (at the moment) feels like mud. When can I replace the soil? Should I wait until spring?
This is what I alluded to earlier when I mentioned water retentive soil. Yes, it must be changed but not now. Late spring is a good time to do Junipers. Have you read the soil sticky at the top of the forum? There is no point in re-potting unless and until you have a grasp of what constitutes a good free-draining soil. You have months though to create or purchase a good mix.