Welcome future Army Officer. Two recommendations from someone about 6 years ahead of you: 1) Kill the nic bitch, 2) Go to Ranger School the first chance you get.
If you think quitting as a Cadet is hard, wait till you get to the real Army where you are surrounded by NCOs and soldiers who all dip or smoke. Quit now and make up your mind about it.
You can do it. I am right now, even while deployed with many coworkers and subordinates who dip or chew...and up my chain of command all the way past Brigade Command there are people who dip or chew. Quit it now and it will be less of an issue when you get to your unit.
Trust me, as someone who has gone through what you are going through, and as someone further down the career track from you...you don't want to have your hands tied to nicotine.