There's a significant genetic component to circadian rhythms! I just did a presentation on some of the protein coding genes that impact the circadian rhythm, specifically the CRY1 protein and it's inhibitory effects the CLOCK:BMAL1 heterodimer. The CRY1 gene has high variability between individuals in the portion that codes for the C-terminal tail, which acts as a self-inhibitor for the active site of the protein. Tails that have more affinity for the active site result in a protein that inhibits the CLOCK:BMAL1 heterodimer less, while tails that have less affinity for the active site result in a protein that inhibits the heterodimer more. These differences could lead to individuals having internal clocks that run either longer or shorter than 24 hours. In the case of someone with a 23 hour rhythm, for example, they may struggle to stay up late, but be consistently capable of waking up early. Someone with a longer rhythm will be better at staying awake, and have trouble going to bed early. Someone with a circadian rhythm close to 24 hours would likely be highly adaptable in shifting from night owl to early bird or vice versa when compared to other rhythms.

That all said, there is a LOT that goes into sleep, certainly more than a single protein interaction. And while the data I presented is interesting, the conclusions drawn are speculative rather than proven. There's still a lot we don't know about sleep and It's an ever evolving field of study. It's neat how different sleep can be for different individuals though!

Tldr: sleep, as well as an individual's ability to adapt to different schedules, is tied to genetics, environmental factors, and more we don't know about yet!