Generally no. There are exceptions though. Like if information was withheld that would of effected her decision or if her plea was unknowing of what it entails or it was not voluntary
since im sure it was done correctly by a judge reading her rights and reading the charge, asking if she understands it to establish a record. I'm going to say shes stuck with whatever plea deal she took.
my best suggestion to you is for you and your girlfriend to have a consultation with a lawyer (usualy free) and ask about a motion to withdraw the guilty plea. He could probably give you your best advice