Well, all of my advice is incredibly dated, as I'm in my mid fifties. Having said that, I'm really proud of you for even entertaining this question. I didn't read your whole post, as what got you here isn't nearly as important as where you go.

First thing.....identify your values. What fulfills you? What genuinely makes you happy? There is no recipe for success, though there are plenty of models for how other people have defined success and achieved it. Success for you may look very, very differently than what you might think it "ought" to be. Living according to your values is the best way to achieve happiness and fulfillment. If you don't know what your values are, find out as soon as you can. Your values will be like the rudder of your ship. Identify what fulfills you, recognize that it may change over time, then act in ways that close the gaps between how you are currently living and what your values are.

Actually, you know what? That's first thing and everything. Do that. Identify your values, find stuff and people that fit into your values, be happy.