I'm somewhat new to the game so sorry if this question is a stupid one and my english isn't the best either so pls excuse that as well ^^.
That being said, I'm unsure how initiating combat with an assassination (rogue assassin) really works.
If i successfully sneak up on someone/something and declare an assassination (or attack), my target and me roll for initiative and combat proceeds. Right?
But that seems kinda weird to me. There could be the possibility of my target rolling a better initiative, going first (but not doing anything bc it is surprised), losing its surprised status on the end of its turn and giving me the turn to attack. This means I wouldn't get advantage (Assassinate ability) bc my target had its turn before me meaning I also wouldn't get my sneak attack bonus (Sneak attack ability) and since the target isn't surprised anymore I also wouldn't do crit damage (Assassinate ability). That just doesn't make any sense to me since I would have attacked from a totally advantageous position an enemy that wouldn't even be aware of me. Did I miss something?
Is my thinking of how this works correct or am I right in suspecting that I missed something?