Can constant anxiety and stress cause high blood pressure? does high bp cause the heart to beat harder and is it rare at 24?

Yes: Anxiety can cause palpitation. Need relaxation techniques, exercise, meditation and set out an hour only to worry and stress. See a counselor

Anxiety shows itself: In may ways. Once can mentally obsess over things that frighten the person or do behaviors to keep danger away, e.g., ritual behaviors, checking and re-checking. Physically there can be heart palpitations, shortness of breath, sweating, sleeplessness, etc. Please go to a mental health professional for support if you think you have an anxiety disorder. See doctor first.