I got confused for a minute- apparently I forgot I had reblogged that thing :)
In an ideal situation I'd be able to list all the specific things you would do well to avoid, but then I wouldn't be me any more and some sort of temporal paradox would destroy the universe. So we'll avoid that. And really, we turn out just fine, so all the mistakes aren't really a big deal. You're going to figure that out, and it's going to be a huge weight off when it happens.
You worry too much, and you already know that. You're the most uptight Taoist in the world, and you already know that, too. You overthink and you fear any loss of control, you're lonely enough to gloss over things that should be addressed, and you're aware all these things are issues. But the main thing is, it doesn't matter nearly as much as you think it does. You're at a place in your life where you think that having a solid definition of yourself is a life goal and a necessity. It really isn't. You'll be a lot happier once you let go of the labeling stuff and realize that we're all flexible, adaptable personalities who expand and contract as we go along. You don't need a rock-solid identity to be stable. In fact, it's rather alarmingly the opposite; letting go of your need to give yourself labels is going to help you relax and give you the space to be a better (and learning!) person. But it's going to take you longer than you'd like to figure it out. That's a part of the process. No one can tell you these things and have you instantly understand; you have to go through them yourself to really get it. It will get easier for you as you get older by sheer weight of experience.
As for your alter-ego, things in your life will follow her story on a basis you will always find spooky, and then at some point it will spook you enough that you'll put it aside for a new one, at least until you're far enough along to want to know how the first one ends. You will have some serious rough patches. You'll get through them. Your friends will have theirs too, and you'll be there for them. You'll fuck it up sometimes, but that's normal. You'll learn that your obsession with being perfect is a facet of the self-hatred that likes to torment you, and you'll learn to fight it and win. In fact you'll learn to fight against all those negative voices and win, although not every day and not every time. But you'll learn while doing it that those negative ideas can be accepted and discarded, like junk mail or spoiled fruit. Most days there's no need to scream at the junk mail, just look at it, say "Hmm, " and drop it in the garbage. It'll come to you, never fear.
You will have horses. They'll be a spiritual, emotional, and artistic endeavour for you. You'll also work harder than you ever have physically and have some fascinating stories about blackout weariness and some permanent scars. You'll be able to tell when it's going to rain with a high percentage of accuracy from a joint or two. The skills you'll bust your ass to gain will keep you afloat at a crucial time period, and also gain you some more stories and some more scars. It's okay, you won't mind too much a year or two after the fact. And the people you get in your life from all the effort are more than worth every injury.
Love is going to be more awesome than you think it is. It's also going to be way more difficult, confusing, and complicated than expected and bits of it are going to suck like nothing has ever sucked before. It's okay; it's a learning experience. It'll be worth it in the end, even that two-year stretch where you bounce between insomnia and hibernation and think about leaping off roofs way more often than is healthy. It's going to teach you some important lessons about guilt, forgiveness, letting go and moving on. And by teach I mean grind it into your psyche with a rusty icepick, but that's okay, you learn better that way sometimes.
Basically it's all going to be an adventure, in the way that as much of it is scary and tough and unpleasant and tiring as it is fun and exciting and broadening and wonderful. But that's okay too. It's all very educational. And you're going to find a use for it when you run across people who are where you are now. So just breathe, stretch, get your chin up, and get out there. Go get 'em, tiger.