It should be OK. I've used starters that were 2 weeks old. It might be a good idea to add a little more yeast to your starter to get the little guys working again.
As I point of reference, I often will repitch yeast by simply collecting it off the bottom of the fermenter. This means it is often 2-3 weeks old. I've never had a problem.
Brody's Brew House
Primary: Sweet Potato Saison(
Seconary: Don't use one, generally
Kegged: Scottish Strong Ale
Planned: Either a Porter or an AIPA. Possibly a RIS.
"For a quart of ale is a dish for a king." - Shakespeare