For answering this sort of question, one needs to consider not only the maximum age but also the boundaries between age categories (childhood, adolescence, adulthood, middle age, old age, and venerable), and these can vary substantially from source to source.
PHBR8 The Complete Book of Elves has a relatively short lifespan for drow; even though a drow doesn't reach adolescence until 50 or adulthood until 80, they reach middle age at 140, old age at 190, and venerable age at 225, meaning the passage of time would ensure that Viconia had reached the venerable age category by BG3, though with a maximum lifespan of 225+3d100, i.e. possibly up to 525 years. This progression is kind of bizarre, though, in comparison to the other elven subgroups listed in that table (page 37).
FOR2 The Drow of the Underdark doesn't seem to include any information about age, except that the maximum for drow is about 600-800, considerably lengthier than the maximum from PHBR8. Moreover, it states that "Drow do not show their age until after their six-hundredth year.", meaning that Viconia would still look the same as in her original appearance unless she had crossed that threshold by the time of BG3. The Menzoberranzan box set seems consistent with FOR2, in that it does not provide any information about age except that the maximum longevity assumed seems the same.
