I am not an aviator (just got selected), but I do have 13 years as an enlisted soldier.
Before I get started I want to let you know that if you do decide to enlist, your recruiter is going to try to make you pick whatever job they can. Go in there with a plan and don't agree to anything unless it is what you wanted. It doesn't count unless it is writing, and you can back out all the way up to signing your papers at MEPS. There is no, "you can get a ranger school slot in basic training". That is not a thing. /rant over
You should finish your degree, before you do anything else. You do not have any other options with the other branches to fly without it, and it will be hard to finish your degree once you join. I left college and joined in 2008, and I just finished my associates degree last year. Deployments, training, and admin work take up a lot of your free time each day.
Also, one of the things that my senior warrant made me do before getting a recommendation was to take a familiarization flight, which I did in a Cessna 152 with one of my friends. This way, if you realize you hate it then you don't owe the Army anything. Study up on whatever you will be flying in, and if you enjoy both the studying and the flight then you at least have a good idea that you may still want to be an aviator. Or if you have the money, you could get a couple hours of rotary wing time and do it that way.