Up to your neck
Sometimes there's no one to help you if you get out of your depth, but that doesn't mean you shouldn't dive in anyway; it all depends on how well you have prepared. This applies whether you want to swim in the sea or do something more substantial with your photography. In fact, it applies to life in general.
One part of preparation is checking your assumptions, making sure you don't make any easily-overlooked logical mistakes. For example, people write hair-raising tales of their travels to countries you would never have the nerve to visit; they tell about a "near-miss here", and re-live "a narrow get-away there". Enough of these exotic tales provide a form of "social proof", leading you to conclude that perhaps it's not so risky after all. You forget that the folks telling their stories are the ones that had the "near-miss"; those that didn't avoid fatal encounters never got the chance to tell their story. This is called "survivorship bias", and the key point is that the negative results are invisible to your decision-making process.
Successful people in business or the arts can relate what actions they took to get where they are, and it is easy to assume that if you do those same things, you too will meet with success. Heck, they sell books and run seminars about it. But that is not the whole story. You can't readily find out the mistakes that they made - and survived - and compare them to the "fatal" mistakes that failed businesses or artists made (if any). I wonder if luck might sometimes be the only difference between success and failure. That's a bitter pill to swallow when you are convinced that it is enough to just try harder, think smarter, persist, and [insert platitude here]...
I'm not trying to kill your dreams. I think that keeping your expectations realistic - even mildly pessimistic - while still having the enthusiasm to give your photographic pursuits a "red-hot go" is a great approach. In short, don't quit your day job just yet.