sentence structure.......?

For the first sentence, I'm not entirely sure what you're trying to say or why you have the word component in there. So I would revise to be: Death is one of the top ten fears among people in my age group (If that's what you're trying to say).

and

Filling in the number 1 slot, Fear of Rejection rates highest among the fears of people in my age group.

While Death is among the top 10 fears of my age group, Fear of Rejection actually ranks first.

Death, unsurprisingly, is one of the top ten fears among people in my age group. Fear of rejection, however, trumps even the fear of death, coming in at #1 on the list.

1. Death is one of the top ten things people in my age group fear most.

2.Being rejected is the number one fear among people of my age group.