Dragons are really weird in this series.
First off, their egg stage is whack; Spit Fyre was the Dragon Boat's son, and she'd been locked up for about a thousand years before Jenna found the egg and gave it Sep, so Spit Fyre's egg must have been laid centuries before Sep arrived.
Plus, the Dragon Boat was a boat for decades before she was locked up - long enough for Hotep-Ra to become an old man - meaning - while we don't know exactly how dragon reproduction works - Spit Fyre must have been fathered decades before he was laid.
Then the egg is incubated for 1yr - 1yr 1/2, and requires some very specific circumstances to hatch, otherwise it dies. Somehow meaning that, as creatures, dragons are simultaneously one of the most resilient, and one of the most fragile, and all this before they hatch.
Then after they hatch, after a very long pre-life period, they mature into functional animals within three days. I recently re-read Flyte, and I had forgotten how close Spit Fyre's hatching was to the end:
He hatches at Zelda's in evening of the day they get there, that's day 1.
He gets back to the Wizard Tower the following evening, and at some point in the night has a massive growth spurt, that's day 2.
He continues to grow and breaks the shadow-safe, and Sep, Jenna, and Beetle discover the placement, that's day three, and before that day is out, he's fledged and big enough for two pre-teens ride.
Literally born on Tuesday, flying about by Thursday.
From there:
He's breathing fyre within a few months, by early on in Physik.
He is fully grown, and an adult, within two years, by the end of Darke.
From conception to hatching, Spit Fyre was around for roughly 1,051 and 1/2 years. Hatching to flight took 3 days, and hatching to adulthood took 2 years. And he will probably live forever. And, apart from being hatched and imprinted by a human, this is all seems to be pretty normal for dragons as a species.
On top of that, if the mood should take him, he might turn into a dragon-object hybrid at any time.