I am a 16 year old female, and I have a blood pressure of 131/74 is that normal?

Prehypertension. A single blood pressure reading above 120/70 mmHg may not be significant in an active teen depending on the circumstances in which it was tested. Elevations of both BP and pulse may occur transiently in response to stress, anxiety and physical activity. Are you obese? We are seeing signs of metabolic syndrome including elevated BP, glucose and lipids in young people with BMI's greater than 30.
That's too high. Granted, it's just one reading, but if your blood pressure numbers tend to run in this range then they're too high.
Upper normal. Recheck at different times of the day.You might be a little nervous if you are not checked very often.