The thing is, iI could never stand watching my friends and my family die before me. The thing is, I could never stand watching my friends and my family die before me.

I would only agreewant to be immortal if alleveryone else in the world could be immortal as well but also if, and there was enough space ion the earth to let live everyone live. I would only want to be immortal if everyone else in the world could be immortal as well, and there was enough space on the earth to let everyone live.

Good job! Just remember to capitalize the "I". I just changed a few words to make the last sentence sound more natural.

I would never be immortal even if iI had the opportunity to, just because it's horrible. I would never be immortal even if I had the opportunity to, just because it's horrible.