Anxiety is a normal reaction to stress. Things like tests, meeting new people, speaking in public, going on a date, and competing in sports can make you feel wary or uneasy.
Anxiety can be a good thing when it helps you deal with a tense situation. For example, when you're studying for a test, a little anxiety can make you want to study hard so you do well. But it can be harmful when it's excessive and irrational and prevents you from being able to focus.
About 13% of teenagers have high enough anxiety to need medication or psychotherapy.