I take EMT night classes x2 a week from 5 to 10 PM at my local community college (tuition is free for me).
It is a lot of dedication, basically another AP class. The 2 days are somewhat close together and depending on the curriculum, expect to stay up late to read the chapters and do the HW. You will sacrifice sleep. My class is kinda rushed, reading 2 chapters within a day on top of other responsibilities isn't fun.
Just to touch of this topic... EMT class is a lot of work, esp if you have no experience in the area. The two days (typically Monday/Wednesday or Tuesday/Thursday) are always rough, since you need to do all of your work in less than 48 hours, and do the reading.
I did my EMT class back during high school in the late 90s, Tuesdays and Thursdays from 6pm to 10pm; now I am teaching a non EMS class at the local CC, two nights a week, on top of my full time job, my part time job, and my family. It does get rough at times
If I could do it all over again, I would get my EMT as soon as possible, and get a part time job in EMS at a reputable company once I graduated high school. if you are going to college, work full time hours over the summer (it's a great side job, and beats working retail). as well as on the weekends. If you want to do paramedic, having EMS experience will help you get that first job.
My two suggestions are as follows: 1) Always always always do the reading before class, and always always always do the homework. And plan to spend 3-4 hours (or however long each class it) in class, doing class related stuff. and 2) treat it as a job... don't be late, don't expect to leave early, come dressed appropriately, and expect to do heavy lifting and hands on activities every single class. Time management is important, so budget your time appropriately. You will need to do this when you get into the real world as well.