All of these suggestions sound helpful. Maybe she could have a special task, like getting the nappy things ready? My eldest liked going shopping with me to find a special toy for my baby boy and felt really chuffed that he took it everywhere with him.

As much involvement as possible through the whole process. Set aside time to do a special activity (nothing fancy) each day with your daughter & plan to do an activity that takes a little more time and effort that really reflects her needs & wants once a week/fortnight. Hope all goes well

By all means encourage your daughter to do things to help with the baby but don’t insist on it too much. I have seen it happen in a few families and it causes an escalation as your baby gets older. Make sure visitors give your daughter as much attention as they do the baby. I have noticed that a lot of people fuss over the baby and the older child is an afterthought and even then it is all about the baby. e.g. saying something like “Have have you got here?” can make the older child feel left out. To make her feel special maybe some of the relatives could give her something special too e.g. a toy to play with or a book to read / amuse her while you are feeding and attending to the baby.

There will probably moments when it is tricky regardless of how well you help her prepare, and that’s ok. Take note of the moments that are working well to reference on tougher days.
Try having the 12yo part of the process, go shopping and pick a special gift or book to give to the baby from her. Also have a special gift when baby is born as a big sister gift from the baby.
Also getting her own baby doll could be helpful for her to process babies… She may like to look after her own baby.

i would tell her up front what you are doing, if sucsessful i would also take her to all the ultrasounds or get a copy and talk her through them at home. I would also make a point that she is a important part of the family who will be needed to help the bubs out…with big siter duties

I’d get her involved in as many activities as possible getting ready for the baby as well as once the newborn has arrived.

Start off small and get her involved. If possible and depending on her understanding have her help along the way. I know a family with a child with the same disorder and they had their child involved and reassured throughout the whole process. Good luck .

If you can get a psychologist involved I think that would be a great help. Also try and involved her as much as possible in the process.

I think there are some great books aimed at kids with disabilities and how to deal with new situations, I wish you well x

Its probably best to get professional advice in your situation – you clearly have a daughter you love and what works for others, may not work for your beautiful family. Specialist child psychologists may be worth seeing during this time of transition and growth in your family.