As spam bot touched on, you're not going to please a lot of roleplayers if you rule with an iron fist. You might want Dalton (player character) to be the one that relays the message to queen Jezebel (NPC) about the incoming sugar dragon invasion. Even though you'd like Dalton and Jezebel to meet up, events in the RP could make this condition very hard to fulfill. Maybe Dalton's player leaves, maybe Dalton tries to take on the sugar dragons himself, or maybe he has ongoing arrangements with another player that prevent him from meeting Jezebel at this time. It would be a lot easier to change that milestone from "Dalton must meet Jezebel" to "[i]Someone[/i] must meet Jezebel," and then try to arrange the fated meeting later if you still feel it would be a cool hook. Most players do not want to help you write a novel, they want to become part of a world that reacts to their actions. It's fine to have hard progression flags for your story, but make sure they aren't so specific that only a single character can activate it.

[url=https://www.roleplayerguild.com/posts/4875611]Dervish's Guide to GMing[/url] is a pretty good read if you're serious about being a GM. But remember that like all things, it takes experience and time to get really good at it. That's not to say your first RP is doomed to fail (mine didn't), but there will be lots of room for improvement!