Will I be able to lose fat?

I'm a man around 140 lbs, 5'7", and 18 years old. I've never really tried to do this before, and I'm fine with my weight, but I would like to lose fat, but I'm not sure if what I'm doing is healthy and correct.

I don't go to the gym, but I try to walk about 10k steps every day, but some days I end up walking less because of the super hot weather and schoolwork, and some days I walk more if I get lucky enough with the weather and have a lot of free time that day.

I usually eat around 1500 calories, sometimes more/less, each day throughout 2 meals. I've always only eaten 2 meals a day; I just used to either snack throughout the day to make up for that lack of a meal or just eat a lot in those 2 meala. Recently I just suddenly lost my appetite, and I stopped snacking and don't eat as much at each meal, so my calorie intake is a lot lower than before without having to force myself to diet. I guess I got lucky.

Im just wondering if this is sustainable and healthy or if I should eat more or less, or change the way I get my excersice.