Be realistic to achieve something.
No matter what you do to create the perfect dream life, you can't create it before you hit the age of 40. In some cases it may be true but those are few examples in this world. Have you ever noticed that once you get older, the mistakes you make do not seem so bad anymore? Or that life seems a little bit simpler? (not in all situations) Let me put it this way. Your life will become a lot simpler and it will become easier to accomplish your goals if you are realistic in life.
If you cannot do something you want to achieve you will feel frustrated and you are going to consume too much energy without any result. You can do too much. Too many people try too hard to find out what will work, try to run large scale trials, or try to copy someone else's techniques without considering their own limitations or personal merits. As a result, failure often results.
“What we like to think of ourselves and what we really are rarely have much in common....”
Evaluate your past performance. Consider what has actually worked in the past. In time, you will learn to apply it to your behavior. Do not let external situations or incentives get in the way. To survive, you have to evolve your strength. Life is a process. Be prepared to adapt to and overcome any obstacle that you are presented with. With practice, you will get better and better at manipulating your environment and your emotions.
Be realistic in your expectations. Expect the best from yourself. Your physical limitations don't change that much. Your mental limitations do. Don't ever get so discouraged that you accept a "second best." That's not real. If someone accuses you of back-pedaling, they are upset because you tried to accomplish your goal, and you failed. Don't engage in that way. Go after your goals and try hard for them you will succeed.
The fact that you got through that struggle successfully does not make you a hero. Getting through the first 15 seconds of exercise does not mean you will be able to get through the rest of your life. All you have done is to demonstrate how far you have come. Keep going. While overcoming your situation will usually take some time, overcoming them is something that is going to happen. Once you come to understand what you can't do, learn how to do it, and commit to it, you will begin to see what the limits are.
Overcome any doubts that may be lingering. I believe that doing what you want to do is going to be the best way to do it, whether you're in an interview or at the gym. Don't accept failure in exchange for getting the job. When you finally do get the job, don't expect a cushy job. Accept the first step of the journey, and move on to the next, bigger step. And above all else, don't give up. If you feel you can't do it, you will get rejected.