Though she can hold a spoon as early as 8 or 9 months, she'll probably use it for banging instead of eating at first. At around 1, she'll be able to make sense of its more practical use -- but it'll be messy, and she'll still prefer to use her fingers.
What to know to ease the transition:
Does she have the skills? Think of all it takes to get food from bowl to mouth. Your child has to be able to:
Hold the spoon the right way up (even if she's gripping it in her fist)
Get some food onto it (sometimes she'll manage this by using her other hand to put it there)
Make the long, drippy trip to her mouth.
Mastering all this takes manual dexterity and hand-eye coordination, which she'll only get better at with a lot of practice.
What you can do to help:
Provide a spoon she can handle and encourage her to try it -- but don't push it. It won't be long before she'll delight in mimicking you and doing things all by herself. When she does start to feed herself, guide her hand if she gets frustrated. Also, make sure she's sitting close to the table and high enough that she doesn't have to reach up.
Serve her thick fare like applesauce, or solids in small pieces, like macaroni and cheese. And remind yourself: The second year of life is supposed to be messy.