Color me impressed.  Blue Ivy Carter, 14, has made Met Gala history as the youngest A-list guest to attend the adults-only invite event in nearly a decade — but hey, when you’re Beyoncé’s kid , trailblazing is in your blood.   Breaking the bash’s long-standing mandate that all attendees must be age 18 and older, the Gen Z daughter of Queen Bey, 44, and rapper Shawn “Jay-Z” Carter, 56, is — evidently — the exception to the rule.   On Monday night, the stylish teen turned heads in an all-white ensemble with an ethereal glow, accessorized with a pair of cool-girl sunglasses. The high-low cut bubble gown and matching jacket draped down the museum’s steps as she, alongside her megastar mama, co-chair of the night’s revelry, dressed to the theme’s “Fashion is Art” motif.  The stylish 14-year-old poses with dad, Jay-Z and mom, Queen Bey, at this year’s Met Gala.…