Yes the younger a person is the higher the rate of PCO. (cloudy membrane behind IOL). In children the capsule is always opened when they have cataract surgery for congenital cataracts. Only your retina surgeon can quantify the risk of RD post Yag and you will need to discuss with her/him.
Hopefully she is just being thorough and alerting you to the risk, rather than having seen signs of it. With modern techniques and IOLs most adults don't get PCO, even if the risk is higher for younger people. I had my cataract surgery at age 52 and was told a couple months postop by a surgeon that he'd bet I'd never get PCO based on how it was healing (and 2 years postop now there are no signs of it). So it seems possible that this doctor saw the opposite in your case, but I would be optimistic if she only made reference to your age rather than commenting on having seen something, that she was just being thorough rather than having seen anything. Its worth asking at a future appointment.