You will have no problem.
Bleach tends to break down fairly quickly, unless it has been very well sealed and not exposed to heat or light. So if yours has been sitting around for a while, it's concentration is already lower. Health departments make restaurants use bleach water for sanitizing tables, counters, etc., and they mandate that it has to be used within a pretty short time after mixing, just due to that issue.
Secondly, the bleach that is present will combine with any dust, dirt and soil in the grass, and dissipate very rapidly. Ask any pool owner about what happens to all his chlorine in a rain storm...