Ok, you've got some bad ideas that need cleaned out. You're young, and assuming you keep going you'll probably get around to that over time like most people do, but I'll try to help on a few things.

First of all, HN and Twitter do not have big problems that need solved around their UIs. When you look at them, you see perceived flaws, but generally speaking those flaws do not matter. People sometimes make the mistake of placing too much emphasis on something because it's what they're particularly interested in, they assume the sun rotates around their favorite thing. What matters is whether users like the product, not whether the UI is mind blowing. HN has a UI choice, not a UI problem. Simple is always better than complex, less is more. You don't build UI to fulfill your ego and show how great a UI wizard you are, you do it to make it easy for a person to interact with a product. When something works, don't 'fix' it on the basis that it isn't ideal. Don't seek out solutions where there are not real problems, you'll just burn your time making a small impact that way. Anyone can look at Craigslist and think that it has a design problem for example; it doesn't: it does what it should and nothing more, whether it's pretty or not does not matter.

Second, you're looking at failure wrong. Failure is your best friend, it will teach you how to become a great entrepreneur. Every time you endure the pain that goes with it, embrace it, dissect it and absorb all the wisdom it has to offer. Zuckerberg has failed a lot, even though Facebook has succeeded overall; he's the first to admit that. Those failures have taught him, molded him, made him better, and without them he could not run Facebook.

If you remain overly scared of failure, then that will make you a terrible entrepreneur, because that kind of fear is crippling. There's a proper middle ground, between recognizing the risk of failure + not wanting to fail, and keeping it out of your mind when it shouldn't be occupying your thoughts (obsessing over it will just paralyze your thinking when it's most critical that you be acting).

Once you see failure is not something that will kill you, and you understand that you will fail many times throughout life no matter what you do, then it stops being an all powerful monster chasing you in your dreams, and it becomes a simple 'thing' you manage as part of the routine.

All the great founders were not way ahead of you at your age. Quite the opposite. You're falling for a hyper romanticized myth that is nothing more than a media lie. Larry Ellison was 33 when he founded Oracle, he's worth 45 billion dollars. Let that sink in for a moment. He's one of the greatest entrepreneurs in history. Larry Page was 25 when he founded Google. Jeff Bezos was 30 when he founded Amazon. Pierre Omidyar was 28 when he founded eBay. Len Bosack was 32 when he founded Cisco with Sandy Lerner. Mitch Kapor was 32 when he founded Lotus. Mark Cuban was 37 when he founded AudioNet. And on and on it goes. Seeing the trend? The typical successful tech founder is closer to 28 to 35 years of age, and absolutely not 19 or 20.

You get back up because it's what you enjoy doing, and failure can not kill you, it teaches you, if you listen to it. I don't even like the phrase "get back up" - why get down to begin with? Yes failure sucks, yes it can hurt a lot, but those things have absolutely no inherent bearing on how you mentally approach the next day, that's up to you to choose. Failure is always in the past, remember that; by the time it's failure, it's already over, don't move in with it and let it stink up the place. On to the next adventure.

Another tip: don't be spaztastic about pursuing things (all over the map, constantly jumping from one thing to another). Be more patient, there is no hurry. Pick one really really good thing, focus on it like a laser; you're a million years of pressure trying to create a diamond from carbon. Success as an entrepreneur rather works the same way as that. It's a grind and it takes time. Or to paraphrase Steve Jobs: put all your wood behind a great arrow.

And this: "My soul will be crushed if I don't realize my potential." --- Dump that way of thinking tomorrow morning, first thing. Strive for excellence, yes. But do not dramatize or glorify any of this stuff. Being an entrepreneur is rubber meets road; it's about getting down in the dirt and building things with your bare hands, so to speak. Does allowing that soul crushed thought into your head design a better product for customers? Not it does not, and it has no place in your head; all it can possibly do is hold you back, trip you up, scare you, make you think of the consequences of failure, and so on. You don't know how long it might take to succeed, it could take five tries and ten years, or it could happen next thing; right place + right time plays so much of a role in all of this, it's impossible to plot success far in advance; you stay on the things you can control: patience, effort, persistence, focus, etc.