"Happiness isn't a destination, it's a realization that things couldn't possibly get any better than having the freedom to perceive as you please and to think as you choose, in a magical, adoring Universe.
Happy? You should be...
The choice remains yours when it comes to deciding how you should feel every single day of your life. Just like anything in life, you are mature enough to make all the choices you want, as long as you assume all responsibilities from these choices. If you succeed, then congrats to you, but if you fail, make sure to brush off this failure and keep on moving forward. F.A.I.L (First Attempt In Learning) is more of a process than a result. Failure is not a result of a chain of errors that you've made throughout your journey in life, but a process to know what to do when faced again with these same challenges. As long as you do not make these same mistakes again, you are good to go. I am not saying that failure will not hit you again, but it will just hit you in different form using different hurdles that are unfamiliar to you. I guess your next question may be: "So, if I understand this correctly, I will end up failing all my life because challenges occur in different formats, from one to the other".
If you learn from past failures, you just don't study that lesson in particular, but your mind will start creating possible alternate solution from that lesson. What I mean is that when faced with a challenge, and learning from your failure, you are amassing more knowledge along the way, which will allow your mind to create more than ONE solution related to a similar challenge from the one you failed from. Since not all hurdles and obstacles in life are the same, they do share some similarities. From these similarities, you create more plausible solutions that will help you in your future when faced with other challenges. Never despair, always try something different, tweak things a little and see what works the best. It is by trying over and over again that you can find solace in knowing that you have done EVERYTHING in your power to succeed. The rest is left to the Universe to decide the outcome of your hard work.