Build on what you have accomplished in this short amount of time. Joint injuries are hard to recover from and can be re-injured very easily. Self doubt is your worse enemy. Remember that a certain percentage of the other people in this sport do nothing else but train for these events. You on the other hand are training and doing many more things and have a full life- an amazing feat if you ask me! So, listen to your gut feelings- they are normally right- and if that means not this year them there will always be next year.......