Im 5'7 and 210 pounds! Can you help?

Hello everyone. Im 5'7, and 210 pounds. I'm a 16 year old male. I know im over weight, because its 210 pounds fat, not muscle. I drink a lot of soda, eat a lot, and all i usually do is play on the computer. I am lazy. But i want to change my life style. I want to know if i stop drinking soda and drink water and maybe go for a mile run a day, that if i would lose some weight? I kinda want to lose a good amount of weight before school start September 7th. My goal weight is 180 pounds. And if i got there, would it be pretty noticeable? Help me please!