This part, though, happened after visiting the NW. It was what got her thinking that maybe the NW had cheated her, iirc right around the same time she notes that she's growing taller.
If she just doesn't want things to change, though, why does she travel? Or, especially, why doesn't she go back to her heritage - the Reshi Isles. Things there seem to be in a permanent stasis, much more so than the rest of Roshar. No, I think there was a cataclysmic change in her life that was not 'just' the death of her mother. I hear what you are saying about processing grief/trauma, but it just doesn't feel right to me. I'm wondering if it was her mother that changed from her idealized image that we've seen so far, to something much less, something bitter or angry or hateful.
Her avoidance of change seems to be for her alone, as if her not changing can prevent something. As you grow up you also have to take responsibility and that is the other way I'm leaning - that by not changing/growing up, she won't have to think about/acknowledge/take responsibility for something she did as a child. Perhaps she abandoned her mother when she needed her most and as long as she is busy with everything as a street urchin she can't/won't have time to think about that. She only has time to think about the good parts, because, "oh look at the time, I need to get some more food to be awesome!" whenever she stops to think.