Hi Dara,
Welcome to our forum. You've asked some really good questions.
It sounds like you want to create something like a social network. Based on what you you indicate as your skill level, (It's impressive that you're self-taught. That's the way I started too.) I would suggest you look at Joomla and Wordpress as options.
Your learning curve with those two will be far shorter than Drupal. Joomla has two very good plugins that have most of the functions you describe already built in.
Take a look at JomSocial and Community builder. We are preparing a mini-course on JomSocial and that might be a good jumpstart for you.
That being said, I have always lived by the adage, "The best software you can use is the one you know how to use." - I made that up, but it's pretty good advice. So if I were you I would put up a couple of test sites. One Joomla and one WordPress and see which one seems most logical to you. They both will do what you want.
I prefer Joomla. To me that's much easier to work with. JomSocial for Joomla is also very complete, and I use that a lot. The most popular CMS right now is WordPress, and second most popular is Joomla. They both will work. They each have a slightly different approach to how they do things, and you will probably find one suits your style better than the other.
Once you decide, our courses and forum help will get you where you want to go with either.
Ask some more questions and we'll keep trying to help you narrow down your choices.
Cheers,
Ed
