Take care of your body and keep it healthy. You have plenty of time to acquire habits helping that and slowly get rid of those damaging it - use that time before the issue is forced on you.
I tell people to keep an eye on their diet. Once you hit your early 20s that whole teen "I can eat a whole pizza and be fine" is gone. It is incredibly easy to go over your calorie needs in a week and after a year you've gained 2-3 lbs or more. Before you know it by 30 or 40 you are 50+ lbs over and obese and now you are struggling to lose it. It creeps up on you.