The last Gundam

(You are the last Gundam pilot) you found a newly built Gundam in a cave, and you activate it, and you've been chosen as the last Gundam pilot in the world, the gundam name is dark death, and your 11, what would you do. The girl, name is Lilly she is 10, she is your sister. What side will you choose the Earth Forces, or Zeon Federation