You also have to consider that you don't know where you'll be financially when it's time to repay the loan. What if you're in a financial pinch and can't make the payments if she defaults?

I agree with Logan, I'd never ask a family member to loan me the money, nor would I loan it to a family member. Money matters can often involve hurt feelings and pain, because different people have different ideas about handling money. Some people are very blase and others are very serious about money issues.