Queen Elizabeth Tiny Royal Subject ... Gets Smacked Up

6/12/2015 12:56 PM PDT

Queen Elizabeth -- Tiny Royal Subject Gets Smacked Up (VIDEO)

Get too close to Queen Elizabeth II, and you might take a shot to the face ... is the lesson a a 6-year-old girl learned at the hand of a Royal Guard.

The little girl, named Maisie, got the chance of a lifetime when she handed flowers and curtsied for QE2 Thursday in Wales.

But watch, right after her moment in the sun, Maisie got a quick reminder life sucks sometimes -- 'cause Lizzie's guard decided to snap off a VERY enthusiastic salute ... and nearly took off the kid's head.

She shook it off -- but someone should be getting an invite for tea at Buckingham Palace.