Hobby Blog - Questions

Hello,

I have been thinking about starting a blog for my two hobbies, coin collecting and vinyl record collecting. I have been looking for a creative outlet to share these hobbies and I was thinking a blog maybe it. I love to write. I have had a family newsletter going for 13 years. I have zero confidence in doing a blog though because there are so many questions.

Who would possibly read my blog?
How do I let people know it is there?
Do I just write about my experiences and knowledge?
Do I treat it like the reader knows nothing about these hobbies and provide facts or just provide websites to look up the facts on their own or both?
Would it be considered appropriate to link to my blog posts on forums?

All the research that I have done on blogging talks about businesses and reaching customers and monetizing, ugh! I have no interest in these things I just want people who share these interests to be able to read my blog and know there is at least one other person out there who enjoys what they enjoy and if they're new to either hobby perhaps I can help. Especially young coin collectors because we need more young people in that hobby.

I already have a platform setup on blogger.com, but I have no idea how good, bad or ugly it is because I haven't done anything with it. I have most of a first blog post written I just need to put it all together and hit the button.

Does anyone have any thoughts, comments, words of encouragement, things not to do, etc.? Anything would be appreciated.

Thank You,
Rich