16 credit limit prior to first day of class…there is a reason for that. Did you ever hear the expression “don’t bite off more than you can chew”…? Even though you might be able to take more than that after the first day of class, I strongly advise against it for your first semester.
Why on earth would you want to do that to yourself? You are a stranger in a strange land and you want to put yourself in a situation where you are under even more stress? It’s your first semester - you need time not only to adjust to the different school demands, but you also need time to develop new friendships, find out what the school has to offer for activities you might want to try…You have 7 semesters after that to really push the limit academically if that’s what you want to do. Ease into it and give yourself some time to explore.
“Really rigorous high school”…yeah, ok. You and everyone else in honors college (and scholars, and likely the majority of students that were admitted to Maryland). New playing field, new game, new rules, new players.
I can’t tell you how many “A” students are overconfident coming into college and underestimate the work they need to. There is so much more freedom in college - both to succeed and to succumb to temptations. Mom won’t be around making sure you go to class, and the school won’t send a note home if you miss class. No one will check to see if you are doing your homework. You are fully responsible for yourself - everything from waking, to making sure you get to the dining hall for meals, to doing your own laundry, to doing assignments, to knowing when to ask for help, to deciding how many social activities you go to, to getting enough sleep, to taking care of yourself when you are sick.
People panic the week before finals when they realize that they don’t know half of what they should because they actually haven’t been keeping up the way they should. In high school, a final is worth what, 10% of your grade for the year? In college, it’s worth a lot more and can totally ruin your grade or save it. In high school, an A is typically the same value as an A-. At Maryland, if you get all A-, you don’t have a 4.0 average, you have a 3.7. No extra credit for an A+ either since it has same value as an A.
It’s great that you want to challenge yourself, but just be smart about it and give yourself a chance to adjust to all the changes. After the first semester, yeah, if you want to take max number of credits, knock yourself out. Just do yourself a favor and don’t do it your very first semester.