Wait a minute!!!

Stop!
I may be able to save you some time here. You said that your grandmother has goldfish, right? (Do you know anyone else who has fish, too?)
If you tell me about it, like the size of the tank, if there is gravel, a filter, etc. I can tell you if you can make a clone of it that will save you a great deal of trouble and anxiety. If it is possible to do this, you will also be able to, safely, put a few fish in right away. I need to have the info about your grandmother's tank to be able to judge whether this can be done without doing any harm to her tank.
You will still need to get test kits, although you can skip the one for ph, and you will need to read the pinned posts so that you have an understanding of the role of bacteria in the process of cycling.
Also, please tell me what equipment you have for the tank. I mean things such as the filter and heater.
The best advice I can give you right now is to stay calm. You are about to establish a tank that will be the basis for a hobby that you can continue for the rest of your life, if you so wish. A week or two more or less, at this point, will not make much difference in the long run.
