Putting everything in letter form is a great idea, let her read the letter and sit right there with her.
Letters are personal and something she may refer back to on her own.
It shows you care about her and her feelings by taking the time to write it to her and only her.
Answer her questions honestly and if you don't know the answer tell her you don't know.
She may feel your opening up as a window into your very protective world and feel closer to you.
Good luck either way.
