Well, if it makes you feel any better, my body fat percentage is usually between 2-3%, and I'm in my mid-thirties, have never been to a gym a day in my life, and eat like a pig.
I hope you're kidding because if you're not then dang you must be extremely toned as you have no fat on you except for the essential. Right now I'm probably at 15% maybe even more. Have put on 25 pounds. That is just crazy. The lowest I've been is 8%. I'm a runner and since I'm currently dealing with an injury I've been gaining plenty of weight.
No, I'm not lying. I'm 6'1" about 160 lbs, maybe gained 5 lbs since high school, which was back in the 90's.
While I have never been to a gym and don't work out, I am active; I play in a men's hockey league (although not in a couple years-too busy), pickup basketball in the summer months, and do a fair amount of bicycling. I walk a lot too; I have never been the type to just 'hop in the car' simply to head to the store 5 minutes down the road.
More than anything though, I just have a ridiculous metabolism. I am fully aware I am blessed in this regard.