new guys has some questions?

I installed WP and plan on using a domain. https://getyourjokeoff.wordpress.com/

I am new to coding and blogging, but I have a few questions. I was going to use the free version as a test and if things took off, I would upgrade. I am going to pay the 13 bucks and use my own domain.

1. When I use my own domain, can I have any redirects pointing on my hosting service to “my domain” . I thought I saw something that said it couldn’t be done.

2. With the free version, am I totally locked out of the back end. I have used WP attached to a website, and was able to make changes in the templet. I have heard of people using WP as their website. I want to take advantage of the blogging capabilities, but I also want to be able to make a site look like a website and not a WP template. Will I have to upgrade or is there a version of WP I can design, and upload to my URL?

3. If I am allowed to make changes with the free version, am I allowed to create greater memory space other than the 3GB?

I know theses are new questions, there is a lot to read that I don’t fully understand. Should I eventually upgrade and have more options or upload a version of WP to my server and customize from there?

Thanks in advance.