Here is a good article that explains the pros and cons of spaying and neutering.
http://www.naiaonline.org/pdfs/LongT...uterInDogs.pdf
In my opinion I would not recommend breeding her at her age. She would likely have more difficultly giving birth and the possibility of complications could be greater. I certainly think it would be wise to get her spayed because intact females as they get older are more susceptible to getting pyometra, which could be life threatening.