Sociology would be a fine choice, just realize that your undergraduate degree, no matter what it's in, isn't going to be terribly helpful in landing you your first HR job. This is primarily due to the tough job market. There are more unemployed, experienced, HR pros out there than there are job openings. It's going to be tough to compete against those with experience. I think Sociology is as good of a choice as anything (that's what I majored in too).
I think you have a good plan though. Get your foot in the door, just doing whatever they need, will help you gain experience and maybe even a job down the road. Like said above, sometimes it's easier to start in other areas related to HR. I started in recruiting as well.