I'll rank it (note: this is NOT my album ranking):
Glory is still relatively new and still sounds fine nowadays but let's try again in 5-10 years
Blackout has that late 00's sound, however, it still sounds pretty fresh today.
In The Zone has some songs that still sound fresh (BOM, Toxic, TOMH) but overall sounds early/mid 00's. Most songs definitely aged.
Circus has aged but not as bad as the ones below
Femme Fatale has that early 10's sound. It did age, but it wouldn't necessarily do that bad today.
BOMT, Oops, Britney are AMAZING albums but they could not be released today.
BJ, no matter when you release it, it sounds pretty bad
Aging is not a bad thing imo. An album can represent an era which you used to love. I feel very nostalgic listening to BOMT and OOPS and love them a lot. I like them better than FF,Circus and obviously BJ.