Baby won't feed herself

I have a 10 1/2 month old daughter, and she will not feed herself. She eats finger food type things like cheerios and puffs, but she will not put them in her own mouth. She barely puts anything in her mouth which I suppose is good in some sense because she doesn't try to eat non-food items or dangerous things. She happily eat them if someone else puts them in her mouth and she will pick them up herself but either end up holding onto them forever or just dropping them to the dog. I have tried guiding her hand to her mouth after she picks one up, but she just screams horribly. Is there a way to help teach them to eat finger foods by themselves? Or is it something that just comes with time when they're ready?