I'm 70. I switched from another clipless pedal at age 67 when I was having difficulty unclipping in "emergency" situations. I talked to the shop owner and he suggested Speedplay Light Action. I've been riding with them (on both bikes) since March 2012 and have never had a problem with unclipping in any situation. Even when I still lived in Atlanta and was riding in their crazy traffic.
Are you twisting your foot (heel outward) to release? Maybe you just need to practice so unclipping becomes second nature.