When in recovery is it ok to start exercising again?

I am following a blog written by a girl who has recovered from anorexia. She was allowed to be active not before she was 2 kilos from the goal weight and having a BMI of 17. I don't have a goal weight, though, so i'm thinking I will wait till I feel I have energy enough and want to be active, and i am afraid I have to wait a long time. This girl have a higher BMI now. I don't know my weight so I can't say what my BMI is. I will ask someone to look at the scale for me once a week to check if I am gaining and to tell me when i have reached a BMI of 18. I hope I have more energy then to start doing yoga at home.http://www.lifewithoutanorexia.com/2014/11/recovery-fatweight-gain-exercise.html

http://www.lifewithoutanorexia.com/2013/06/exercisemy-workouts-part-

http://www.lifewithoutanorexia.com/2014/07/exercise-and-how-i-built-up-strength.html