First, congratulations on taking your health and fitness seriously. Taking the time to exercise is a big deal and I hope you make it a long term goal.
Many experts recommend morning exercises as the best, especially before breakfast.
Personally though, I don't believe that the time of the day matters. What matters is the consistency and intensity. 1000 calories burned during the day is the same as 1000 calories burned at night. If night workout fits with your schedule and you're consistent with it, you'll see optimal results. If day workout's your thing, you'll see identical results too.
I haven't read any article about the body's ability to lose calories based on the time of the day. However, a lot of people exercise in the evenings because it's much comfortable for them to do so. They are more relaxed, have more time, or have difficulty exercising in the mornings.
So, as long as you're consistent in your workout routines and maintain a good nutrition, you should be healthy and strong.
Equally important, don't make your workout time the only time you exercise. Try to incorporate exercising into your daily routine. A quick 10-rep squats after sitting in a chair for a while can give your body a quick calorie burn (in less than 20 seconds). So is a quick 10-rep push up.