My mom went through the same thing ten years ago at the age of 66. Small tumor, 1.00cm, no lymph node involvement, lumpectomy and radiation for six weeks. She's been fine so far.
The tumor is small, if she has no lymph node involvement (they'll check when the do the lumpectomy either with sentinal node biopsy or just taking a few nodes) she is pretty sure to be ok. If they can get a clean margin around the tumor when they do the lumpectomy and no node involvement she'll be even better off.
The radiation treatment is not that bad, it's more of a pain because you go everyday. It's quick though, like 10 minutes. It does wipe you out in the later weeks and you feel tired and does some funky stuff to your skin but it's doable.
It's scary, I've been through it for myself and for my mom. The initial weeks are the worst, once the lumpectomy happens and the radiation starts the stress seems to lessen. Ask questions, lots of them and go hit your library or book store for books. There are alot of good books out there and they seemed to help me when I couldn't remember what the doctor just told me because I was so stressed out. I'd hear what they were saying but didn't absorb it, reading it later helped alot. Susan Love's books are the best!!