Taurine is not a treatment for all heart conditions. Most dog foods have adequate supplies. Taurine is used to treat cardiomyopathy (a specific heart issue) and has been found useful in cardiomyopathy caused by or associated with grain free diets.
Some heart murmurs are innocent, I've heard a few while an animal was under anesthetic but not when awake. Further testing - echocardiogram is probably the best course to get the information necessary to make informed decisions.
As Bob/Olallawa said "Better to get her on the meds soon to help keep the progression at a slower rate." This is the current thinking most veterinary cardiologists ascribe to.
I've had patients diagnosed at this age and go on to 15+ years of age, with the cause of death unrelated to the heart condition. But there are some that deteriorate fairly rapidly (within years). It all depends on cause.
Doug, DVM