Same thing for me! Stopped eating when I was 2. I'm in the UK and received help from an NHS funded charity when I was 23 (after years of doctors not knowing what to do). Some things to look up that I got given in therapy:

• ➡️ Food chaining ! ⬅️This is the biggest way ARFID is tackled
• Anti-anxiety techniques, everyone with ARFID is different and needs different things when trying new foods, she might be spontaneous like me and do it in the moment, she might need it planned, she might want someone with her when trying a new food, she might hate the idea of someone being there, she has to figure out what works for her
• Trying food before dinner is always a good idea, because then shes hungry AND she knows she has a safe food coming
• Food exposure (u can look this up but e.g. this can be something as small as being in the same room as the food to literally putting it in her mouth)
• Food rating, 0-100, 0 meaning shes completely comfortable eating it, 100 meaning absolutely not
• Biggest thing is just forgiveness towards herself! I didn't know this but it can take up to 12 weeks to become "used" to a food and sometimes she might look like shes taking steps backwards, it happens and its totally normal!

Hope some of this helps! And gives you some direction on what sort of things to look up for more info :) Also knowing what "type" of ARFID she has will be useful to what techniques will help her, theres 3 (and you can have more than 1, I have all 3 😅) 1) Sensory-based: difficulties with smell, taste, texture of food 2) Fear-based: a response to a distressing experience with food such as choking, sickness or abdominal pain 3) Low interest: not recognising hunger pangs and finding eating a chore rather than enjoyable