I have only 5 sessions left before I finish the couch to 5k course. I have arthritis (including my knees) and before starting it I had lost 3 stone in weight. I was worried I wouldn't be able to get this far and each session I wondered if it was my last but by sticking to resting between sessions I could carry on. Here are some things you might want to know (from my perspective at least):
It's not always easy (but feels great at the end of each session)
It hurt my knees sometimes
Mind over matter works - don't give up
It doesn't matter if you don't run terribly fast
Be proud of yourself
Finally, if I can do it - so can you!