Not Cathe, but I hope I can help...
I remember her responding to a post like this before and I have read up on this myself to a degree...
Workout when it is best for you, when you feel most "awake" and ready to exercise, most importantly don't put it off as an excuse until the end of the day because that can lead to not working out at all. But like you said it is because of school.
Working out first thing in the morning I have read is the best time to workout, but not best for every person, there isn't a "one size fits all" for exercise, you have to be the judge of what time works best for you.
I have tried to workout in the morning, but I don't get as much out of it as when I am working out in the afternoon. When I workout in the afternoon I am more into my workout, jumping higher and going longer than if I workout in the morning. So the morning workout advise doesn't work for me either.
However you should not work out at least 3 hours before going to bed. There is a reason for this but I can't be specific because I don't remember. You need to have at least 3 hours to return to as close to resting heart rate before you go to bed. So if you work out at 8 and end at 9 don't go to bed until 12.
Hope that helps you! But again workout times are not a "one size fits all" You have to find what works best for you and go with it.