The fuller answer
Checking can begin as an attempt to get certainty: measuring, searching, comparing photos, asking the same question, or inspecting a body part. Relief usually lasts briefly, so the brain asks for another check.
The problem is not curiosity. It is the loop: trigger, anxiety, checking, short relief, and stronger doubt. More precise numbers do not reliably solve a fear whose real demand is perfect certainty.
Comparison anxiety can affect any body feature, puberty milestone, sexual history, family situation, grades, money, or social life. Cognitive-behavioral therapy and support for obsessive or body-image symptoms can help.