Understanding the timeline was not Shuchang's strong suit; he only knew that if the existence of something on a certain timeline ranged from one to ten, then ten was its limit, and even reversing cause and effect could not change it.
This little girl was exactly that case.
Her current height was her limit, something that could never be changed.
On the other hand, Shuchang could change his state, progressing from the initial stage of Heavenly Gang Cultivation all the way to the Extreme of Heavenly Gang, thanks to the special nature of the Cultivation Land.
The Cultivation Land allowed him to temporarily withdraw from the influence of the timeline.
This was also why, when the little girl was about to make her breakthrough to the second level of unity, he went to her directly.
Saving her was just a matter of convenience.
The main reason was to have her put off her breakthrough.