If you noticed, the first part of choosing a topic required you to do some background research. Sometimes researchers select a topic, and then try to research it, often much later.
This can lead to a few problems:
As a result, finding information can to be frustrating, and may yield results that are less than ideal.
The simple step of researching as a topic is selected can often make the entire process much easier. This can be done if you follow these steps.
When you are doing background research on your topic you want to consult reference sources. These can be encyclopedias found in the library or online; and yes, in this preliminary phase of research you can use Wikipedia. Never cite Wikipedia in an academic paper, but if you are deciding if a topic interests you, go for it. Just remember that Wikipedia is not consistent and while one entry might be accurate another one may not be.