I love guinea pigs! They need a lot of handling at a young age to make good lap pets, but I've had pretty good luck calming piggies of all ages.
Try setting her in you lap without holding on. If she tries to run off, catch her but don't hold on to her unless you absolutely have to. Gradually begin to pet her and scratch the places where she seems to enjoy it. You have to keep it up a little every day, even several times a day. Letting her eat her fresh veggies and her special treats while sitting in your lap will help her relax and enjoy the time you spend with her.
It will also help to have her cage in a room where you spend a lot of time. Shutting her up in a bedroom or other room doesn't give her much of a chance to get used to the sight and sound of you.
Beginning a relationship with a one year old can be hard, but once the two of you click it's worth the time and patience put into it.