yeap, it's time for a new battery.

"mainly run 2-3 mile one way to and from work daily in the past one year" This is what kills the battery. It has been too short of the driving to get the battery fully changed, the longer it's not fully changed the shorter its life is, but average life of the battery is up to 6 years, 8 years of yours is very good. So give it a big thank-you for its excellence, and get a new one hoping the new one will treat you as well as this one did.

But it doesn't hurt to get it tested at Auto zone in case it refuses to die.