Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency care for a severe sudden headache, loss of vision, confusion, fainting, trouble breathing, a seizure, or severe weakness.
Short stature alone is not an emergency.
Seek prompt medical advice for short stature accompanied by persistent headaches, changes in vision, repeated vomiting, marked thirst and urination, or new weakness.
These symptoms do not usually result from short stature, but they may point to an underlying condition.
Arrange a routine appointment if a child appears much shorter than peers, is below the lowest lines on a growth chart, or has not had height measured accurately over time.
The article also says
Assessment is also appropriate if the child:
Is dropping across height percentiles
Is growing much more slowly than before
Has poor weight gain or unexpected weight loss
Has ongoing digestive, breathing, kidney, joint, or fatigue symptoms
Shows no signs of puberty by the expected age range
Has body proportions or physical features that seem unusual
Was born small and has not shown expected catch-up growth
Every sign above is quoted from the sofidex article on Short stature. If you are not sure, err upward — it is always reasonable to be checked.