Although I do think that questions are a good thing, so I don’t think every single detail needs to be provided ahead of time. Only the most relevant and obvious. Leaving the chance for players to ask questions is key, I think. It’s often a sign that they’re engaged and want to know more.
IMO that's good for both player engagement and player agency. When the player zooms in on specific aspects of the narration, and asks about those aspects, then that can also indicate where the character is directing their attention, and what the character is prioritizing.
We humans don't process every detail in our field of vision. We pay more attention to some than to others. This reflects our priorities. Same for PCs.
DM: "A dragon swoops down towards you!"
Player A asks whether it's shiny, because Character A thinks in terms of alignment tendencies. Character A might overlook other details, while zooming in on whether this dragon is metallic.
Player B asks how large it is, because Character B, the battle master, is more interested in a tactical threat assessment (young dragon versus huge ancient dragon) than in guessing its intentions.
Player C asks whether it's unambiguously a literal dragon, because character C is a sage, and wary of false conclusions from first impressions. Character C is double-checking: is this actually a wyvern, or a pseudo dragon, or a dracolich, or something else which we might *confuse* with a dragon?
Player D asks whether the dragon is carrying any items, because Player D's character only cares about monsters in terms of what loot they drop. I'm not saying this is a good trait, but it happens. (Player D finds it entirely reasonable that in WoW, you can kill a vulture, and afterwards, find a glass of vulture milk, upright on the ground, not a drop spilled.)
These are all valid questions - well, at least three out of four are valid - and the GM is wise not to put the answers to ALL of them into the initial narration. All of the PCs see a dragon; each PC notices different details, varying according to their priorities - and their skills, if some questions provoke INT checks (possibly involving proficiencies such as History or Arcana).
If the dragon immediately zooms away, and the PCs don't get a sustained opportunity to observe the dragon, perhaps the PCs would benefit from trading notes. You know, like a team made up of diverse specialists.