Again? A real shame considering what she achieved, but it seems she just isn’t up to it physically. She’s 19, she should be in her prime.
It doesn't work like that. The difference between a 19 year old and a 25 year old in a lot of sports is quite large. It depends how people develop. They are still playing under 21s international football. If all 19 year olds were fully ready for the rigours and pace of the professional game they wouldn't have that.
When she is a few years older and has had time to properly adapt to the elite level game we will find out if she has the body for it.