Oh sweetie I'm thinking of you today. Try not to worry, love, it IS peaceful and very, very quick. Just a little needle p-ick and off to sleep straight away. Big, big, big hugs to you, hun. Will your DH be with her? Some vets take the pet out the back to save the owner the pain of seeing their pet pass, but honestly I'd rather be there to comfort her as it happens, kwim?
All the best hun, I'm so sorry. My condolences
x