How much weight can i lose on this diet im trying to lose 20 pounds at least?

im 152 pounds im "5 9" im 16 years old im trying to get a flat tummy toned little bit, everyday routine, wake up at 6:30 get ready have 2 eggs with 1 fruit with either green tea or water, and after i do 30 situps then at lunch i have salad and fruit with water, and i walk home 45 mins if im hungary fruit, dinner chicken with veggies, every day i either have volley ball cl or aerobics cl at school im trying to stay away from junkfood, my family likes to bring junk food i try to hide it so i cant get rid of the junk food i have 4 months or less before summer i cant run because its hard for me i can run like 1 min then i get tired easy on weekends i try to be out of the house either with friends or family im trying get active and lose 20 pounds or more every time i go to the store i always see sweets junk food i have craving how to get rid of craving for junk food i try to exercise but i have choirs and things do so help me please i cant buy diet pills i want a healthy way so is a good diet plan