I don’t have an ED, but I think if you want to write about it, you should do a lot of heavy research. I’ll link some things like how to write abt an ED, and stories by people who do have EDs.
Resources
https://www.google.com/amp/s/psychwriter.com.au/2018/01/14/eating-disorders-anorexia-nervosa/amp/
On the Literature of Eating Disorders ‹ Literary Hub
Reddit - writing - Advice for writing anorexic character?
Sara's Story - Kelty Eating Disorders
Bodywhys | Claire's Story
Patient Story: Eating Disorders
Also remember that’s there’s different types of eating disorders and eating disorders can look like anything and can affect anyone of any size