There is an idea among us that Christ was born with power over death. But Joseph Smith clearly taught that in his youth, the Savior was subject to death. Speaking of Christ, Joseph Smith said:
When still a boy He had all the intelligence necessary to enable Him to rule and govern the kingdom of the Jews, and could reason with the wisest and most profound doctors of law and divinity, and make their theories and practice to appear like folly compared with the wisdom He possessed; but He was a boy only, and lacked physical strength even to defend His own person; and was subject to cold, to hunger and to death. (TPJS page 392)
But then, how did Christ gain power over death?
The scriptures say that Christ was given power over death by his Father. And have we not seen such a thing before, for in the fragment of John the Beloved's record we have in D&C 7 we read
D&C 7: 1 And the Lord said unto me: John, my beloved, what desirest thou? For if you shall ask what you will, it shall be granted unto you.
2 And I said unto him: Lord, give unto me power over death, that I may live and bring souls unto thee.
3 And the Lord said unto me: Verily, verily, I say unto thee, because thou desirest this thou shalt tarry until I come in my glory, and shalt prophesy before nations, kindreds, tongues and people.
So yes, Christ had power over death. It was given to him by his Father, as it was given by himself to John the Beloved, and to the three Nephites.
Which is interesting, because Christ himself calls the power he received over death a "commandment" from his Father, rather than a physical inheritance.
John 10: 17 Therefore doth my Father love me, because I lay down my life, that I might take it again.
18 No man taketh it from me, but I lay it down of myself. I have power to lay it down, and I have power to take it again. This commandment have I received of my Father.
None of these others could have conquered death, the way Christ did. But all had power over death. All, like those taken into the paradise of Zion, had power over the grave.