Everyone gave you good advice. However, I want to add that you can start with a blogspot blog.
Most people don't succeed with their first blog. But they learn a lot of things. There is a good chance you'll not make much from your first blog. But it'll tell you if blogging is your thing or not.
- Researching about a topic,
- finding keywords,
- posting articles,
- building a good navigational structure,
- adding to different search engines,
- promoting it on social media,
- building links,
- getting traffic,
- testing different monetization methods
This is about 90% of the things that you'll do with your blog. WordPress, blogger or any other CMS it doesn't matter. Basic things are almost same on every platform. All of the above is possible on blogger. You don't have to pay a dime while you're learning. So why not start from today and try to build something?
And then when you're confident, you can point your blog to your own domain which may cost $10/year.