Yes. What is not taken into account is that God, the angels, and Lucifer existed in eternity long before the creation when measurement of time began. So we don't know exactly when Lucifer's rebellion happened in eternity past, because eternity past was a very long time and the rebellion could have happened at any time during that period, long before the creation of the universe was even a thought in God's mind.
We've already talked a little about the meaning of eternity, and I must state why I find your usage troubling. Please understand, I am not saying this about you, but of the LDS.
In their theology, all of us are eternal spirits alive in eternal heaven. At birth our eternal spirits enter bodies so we can live in the physical creation. If you are good Mormon, then after you die, you will have many wives to populate a planet that you become the god on.
There god, Elohim, is just another eternal spirit that left eternal heaven and populated Earth. Adam, Elohim's first man fell into sin and Jesus and Lucifer (who are brother eternal spirits) come up with 2 different plans of salvation. Jesus's plan was accepted, so Mormons have to believe in Jesus therefore consider themselves Christians, too.
This Jesus, (like the Watchertower Jesus who they believe to be Michael the arch angel) is a different Jesus than the Jesus of the Bible who is Yahweh Shua, I AM Salvation.
This is why I believe there is a difference between eternity and everlasting. Eternity means no beginning nor end. Everlasting means a beginning but no end. It is the eternal nature of God that prevents Him from being able to sin.
A systematic theology book I read parts of years ago used the analogy of parallel lines to describe eternity. Parallel lines, but definition extend in both directions without end and never cross. If those lines could cross anywhere, then they would not be parallel lines.
It is precisely because God has no beginning nor end that it is impossible for him to sin. Because he is always holy and can never be unholy.
Do you see the problem? If we were also eternal spirits, as the Mormons believe, then it would also be impossible for us to sin, too. There could be no fall. But a segment of a line has a beginning and an end. Therefore it can change.
Likewise with Lucifer and the angels. If they are eternal spirits then it would be impossible for them to sin, too.
I may have errors in my logic, and if you see them, please point them out.