Older child + twins = scared?????????

Kate • 29 - 2ectopics now proud mama of 10yr old & 6mth twin girls xx
Well I have 9yr old daughter, we've tried for years & years to give her a sibling she has been so desparate for one but we had two consecutive ectopics (which she doesn't know about). I think she is now just used to & happy being an 'only kid'. 
However we have just naturally concieved..... TWINS!!!!!!!!!!!!!!!!!
I'm frightened for my daughter - I feel she might feel even more alone & lonely than being an only child because these twins will have this amazing bond etc etc. I'm so scared that my longing for a sibling will make her even more alone :'( I plan to make her mega involved I know she will be a great help when they are little but I worry when they grow she will be left out.
Does anyone have experience of going from having one older child - to a sudden set of twins on top????