Welcome to Beesource!
And, a lefthanded welcome to beekeeping, from the bees. 8 yards is a good distance I would consider safe from the flight path, where it seems 85% of the stings occur, but it can happen, and without provocation, but only very rarely without provocation.
Was anybody eating a banana? The smell is very similar to their alarm pheromone, by which they call for backup from their sisters. That would be considered provocation enough from a hive that had experienced any difficulties recently.
Did anybody make a sudden move? Was she wearing flower-scented perfume? Wearing bright colors? They have all figured in to some stinging incidents.
Head-butting is a "polite" warning requesting one to please remove one's self from the flight path, and to please give the hive a bit more inter-personal space. Stinging comes next.
Worst case is a full-blown attack, which is usually the bees 17 to 19 days old, plus any others that smell the alarm pheromone and hear the vocal call. In this case, retreat indoors, jump into the pool, cover with a blanket, whatever works if you do not have your bee suit on. Help one another remove stingers ASAP, as they have the poison "pumps" attached and are actively adding poison as they remain poked into your skin. A credit card is an excellent tool for sting removal. Use a brushing motion in the "out" direction, if you can see it well enough.
Any major stinging event - upwards of 30 stings, watch carefully for symptoms of shock. Constricting of the airway, dizziness, difficulty breathing, confusion, change in heart rate, muscular trembling, in addition to the usual symptoms of a stinging - pain, itch, and swelling are cause for immediate medical attention. If you have an Epi-pen, use it. It is a potential life saver.