It's not that their ages were too different, nor that Tang Li's limbs were abnormal, but rather...
Zhan Tingzhi's heart was simply not set on Tang Li.
Tang Huai would rather believe those letters were written by someone else than by Tang Li.
Tang Huai didn't have high expectations for Tang Li; as long as she lived better than she did in her past life, that would be enough.
In her previous life, she never married, not because she didn't want to but because her limbs were abnormal, she couldn't farm, couldn't do much fieldwork, and was despised by others.
The resentment that accumulated over the years was all taken out on Liu Xiaoyu, ultimately turning her into a bitter woman.
In this life, Tang Huai hoped that Tang Li wouldn't follow the path of her past life and would understand that their parents had had their own difficulties in not taking her to a doctor.
She hoped Tang Li wouldn't resent life or complain about her relatives because of her abnormal limbs.