There is a certain life decision which I am facing and I just don't know what to decide. What's more, it's not entirely dependent on me, but also whether I'll be accepted even if I apply. Ultimately, I feel I'm procrastinating starting the process because I'm afraid I'll be rejected, and I don't want that. On the other hand, without applying, there's certainly no chance of being accepted. The things that have happened in my life until now seem to point in that direction, but how can I know if it's right for me, or deal with applying and then being denied?
I empathize with your mixed emotions and doubts. We all take our life path seriously, and it's natural to be concerned about the choices we make and the impact they'll have on our fulfilling our purpose in life.
That being said, I'll try to outline a few guidelines which I hope will help you in this situation, as well as in other decisions that you will face in life.
The first thing is that you have to really search yourself to determine if this is really what you want to choose, and if it's really for the best. Even if you want a certain thing, that doesn't mean that you should choose it. Every possible factor should be taken into consideration, such that given these other factors one might choose to forgo this particular thing. As a simple example, even if one really wants a particular job, its requiring a particular location or separation might render the desired thing an undesirable decision.
Once you've weighed every possible consideration (and making a list of pros and cons can help here), such that you feel this option is the desirable choice, you should then consult someone who knows you well and whose opinion you value. This is important for at least two reasons: One, as objective as one tries to be, we are biased when it comes to ourselves. This, plus our being embroiled in doubt, will most likely cloud our vision. Two, try as we may to factor in all considerations, there will always be points, nuances or ramifications which we overlook. Consulting another person, particularly if he or she is older, more experienced, or more insightful can only help.
Another very important factor, particularly for someone like you who is consulting a rabbi, is to make sure that what you're considering is acceptable according to the Torah; and if there are any problems, whether and how they could be surmounted. Often, plans that seem positive, constructive and worth pursuing can actually be problematic according to Jewish law, ethics or philosophy. It is therefore very important to consult a competent rabbi about what you're considering in order to make sure you're not missing something on the Jewish side of things.
Once all this has been done, and you've invested all you could in order to make the right decision – go for it! This should then be done with the belief that if it is really the right thing for you now, G-d will grant you success. But if you do not succeed, it should be understood as a sign that this is either not the best for you, or at least not for now. So there's nothing to be worried or upset about.
Regarding those scenarios where the pieces of the puzzle seem to have been leading in a particular direction, and you make the relevant decision only to be forestalled - not to worry. If this happens, as in puzzle building, perhaps you thought these pieces were parts of one puzzle, when in fact they were mixed into the box, and it's now your job to think out of this box and integrate them into another picture. Alternatively, even in the same puzzle, oftentimes pieces start fitting in one direction until all of a sudden they start moving in a totally different direction. In order to complete the entire picture, sometimes you're forced to leave part of it unfinished until you're led back to it through filling out other parts first.