She's coming home and is very afraid of shots.
Needle phobia is certainly a challenge at any age.
My suggestion would be to hook your daughter up with another 12 year old who has had diabetes longer and is unafraid of injections. Let her get some tips on how to lessen the pain and overcome the fear. Most of all, do not take over the responsibility for injections yourself. It is your child who has the diabetes and must learn to manage it. You can assist her.