Michelle,
I used to think very much like you do on my invincibility (for lack of a better word).
Then life happened and I reacted poorly.
I discovered that when you start to fall, often you fall much farther than you ever imagined possible—because of the nature of gravity, not because of any failure on your part. You suddenly see yourself doing things you thought simply impossible before. Things that are just not you. This does not mean that the start of the fall was not your failure, but that once a fall starts, it develops a nature of its own in addition to your initial failure and you get carried along.
There is some truth to the saying that the bigger you are, the harder you fall.
Now, since I am a real hardhead, I fell twice in the same manner. I was once addicted to alcohol. After I got over that, I fell off into crack cocaine. About 5 years each stint.
Maybe I needed two falls to widen my view. I used to be really blind about some things. I think the best thing I ever learned from this is on a sense-of-life level: I now know all the way down to my toes that I am not greater than reality.
It may sound silly, but I needed to learn that.
I used to have what I call a cognitive-normative inversion, where evaluation came before fact in my mind. (This is a huge problem with many Objectivists to this day.) In order to survive my falls, I had to learn the proper order on a premise level. In other words, identify, then evaluate.
It works, too.
This led to me checking every single principle I had ever adopted.
I was so delighted with the result that now I periodically check my principles on principle. Rand's phrase, "check your premises," is a great procedure to use periodically on all premises, even (and especially) hers.
If certainty in thinking is a value that led you to Objectivism (I know it was to me), this procedure provides much more certainty than the evaluate before identify temptation, often called euphemisms like "thinking in principles," or "Romanticism." There are some other colorful and cool-sounding names in the jargon.
Don't get me wrong. Thinking in principles when you should, or having a Romantic sense-of-life when you truly understand where it applies and where it doesn't, are perfect forms of mental activity that come with enormous benefits. With improper use, though, they become crutches and lead to all kinds of errors and heartaches and, especially, underachievement.
Here is one example (and there are many I could mention). Rand was an adamant proponent of love at first sight. When it works, the Romantic sense of life aligns with reality and it is wonderful. But love at first sight is basically a crapshoot. A person doggedly holding onto a horrible relationship because the he or she felt their sense of life could not have been wrong ("could have betrayed them" or something like that is how it is usually expressed) will get hurt. Really badly.
It's heaven being in love with the right person. It's hell being in love with an illusion. And it's not as easy as people make out to stop when you find out you are wrong.
There is a well-known fact about the Objectivist world: there are many failed relationships within it. I believe the cognitive-normative inversion is one of the main reasons.
I had to learn how to do it right—how to keep to the facts while keeping the passion going. I learned it the hard way, but I learned.
Now I have true certainty whereas before I had the allure of certainty and kept telling myself I had it. For example, I can say with total certainty, if I had to do it all over again, I would have done it differently. Coming out of that mess was no picnic.
But I don't know how I could have done it differently. Like I said, I was real hardheaded.
Still am...
Michael