I am a 16 y.o. female at 190lbs wanting to be 165. how many calories should i consume and what walking or running exercises should i do and how long?

Calculate3500Cal 1lb: You need to loose 25 lbs.you have to have combination of daily calories from your diet and burning some calories by exercise.You have to be negative 3500 calories to loose1 lbl of body weight. So it means if you need 3000 calories to maintain your weight of 190.So if you cut your calories down by 250 Calories and burn 250 by doing exercise like running,bicycling.3500cals loss/week.25lb in25Weeks