hahaha don't worry about not being proactive man.. well actually you should worry about it, it means you realize your problem, all you need to do is act on it, but you are 19 years old? youre gonna evolve like a pokemon now, in 5 years time you will look back at how you are now and you will see how different you became, and with a good core like the one you have I am sure you will change so much for the better.
IMO, its good that you know what is good for you and what is not, but it is equally important to know WHY this is so. Personally, I dont like to regret over things so I prefer to learn something from my past mistakes, although thankfully I don't consider them to be so bad, rather I see them as just a phase that I needed to go through to realize that what I had was good enough to begin with.