Jun Wu Xie witnessed the whole process with her own eyes, but what she cared most about was Elder Luo's remarks about the potion.
Within the Three Realms, the only way to keep one's appearance unchanged was to practise hard with one's spiritual power. The stronger the spiritual power, the aging speed will slow down even more. Just like Jun Wu Xie, after she inherited Grandmaster's Spirit Ring, during those five years of silence, the changes in her appearance were very subtle.
Furthermore, with Su Ya's age, her looks were completely inconsistent, but because her spiritual power was very strong, it could maintain her looks without outright aging.
But...
The Sacred Maiden Tribe did not have a high innate aptitude for spiritual power. However, within the Sacred Maiden Tribe, Jun Wu Xie had not seen any aging persons. The people here, no matter what their status and ages were looked at most, in their early twenties. There was no hint of aging at all.