Probably not. In reality, she would probably boss the baby around.
You can check online at petfinder.com and search for guinea pigs available near you. Most guinea pig rescues will let you leave your guinea pig there for a few days and they will try out different possible friends for your guinea pig. Not all guinea pigs get along just because they are social though. Keep in mind it may take a while to find that perfect partner for your guinea. If she is not spayed, make sure she's paired up with a female, or a male who is neutered.
Good luck with your search!
EDIT: The above person is wrong. She will not kill it. Hamsters are more likely to kill babies, or even their partners. Guinea pigs are not violent. Also, as long as you're spending at lest 2 hours a day with the guinea pig, there is no need for a friend!