I have taught middle school and high school camping classes and have taken students on over nights. I’m not at all familiar with Maryland trails. However you asked for suggestions on preparing them for a hike.
The first thing you need to consider is the number of students. I would take no more than 8 people in the group, counting parents and teachers. It is recommended by the ATC to limit the number of people in groups on the AT. If it is not on the AT take 3 or 4 more people. No more than 12.
If you have time, set some type of physical limits on the students. Give them some type of goal to reach before going: be able to walk 2 miles under 20 or 15 minutes, be able to walk for an hour with a backpack, walk around the track or school campus.
Students must be able to set up the tent in which they will be using, have a menu, clothing check, etc. Above all, be ready for bad weather. The first time I took students out it rained the first night, students and gear were completely soaked, we ended the trip early and it was a nightmare. Make sure you have a good first aid supply kit. The more people you take the higher the odds you will need first aid.
Check different websites, there are many sites that will give you check lists to make sure everything is covered.
You know the students the best, if you think you will have trouble or problems with one or two, leave them at home. Good luck with your trip, start small and if you come back wanting to go again considerated successful.
Bilko