Beforehand, I'd described Elly as being much like her children. Whenever Mike or Liz are done poisoning the well like idiots, they think that they've taken the blame off the person they've mistreated by declaring that they only thought that they were in love with whoever dodged the Patterbullet but they didn't know what love means until that moment. In Elly's case, it seemed to me that when Elly talks about taking her appearance in stride, she actually meant "Oh, well, I did panic back then but I was wrong to think I looked old and fat but I'm not wrong now."
What really seems to be happening is that each and every time that Elly changes from someone aging gracefully to someone freaking out about looking like an old lady, Lynn's inability to clearly remember what she did last time and reluctance to find out probably mean that it happens for the first time every year. Lynn's poor technique thus means that we have the worst of both worlds in which we repeat old gags AND have the characters age in real-ish time.