I can't really help you doubt why you shouldn't go. Haha my parents are ESTJ and ISxJ, and they've both made it their goal to socialize me as well, it seems. I remember them often telling me to have people over to play, when I was in elementary school. Later they turned their attention towards trying to get me to stop socially-unacceptable things (twitchy eye movements, looking at people while I talk to them, comb/cut hair somewhat short, don't spit out in public, wear shoes when I went out places, look up while I'm walking, etc). I'm not sure if your ESFJ mom's promptings were that nitpicky/controlling/frustrating, but when I left for college, I actually found out that most of the reason I did those things in the first place was because I was under constant watch/criticism. Within three days I had my head raised and looked around while I walked places, and within a week or two I was mostly-twitch free. Though the twitching does come back occasionally. I also found that virtually nobody cared about the same things they did (though I did go to a very high-quality college, so it was filled with an extremely lopsided population of N-types, which I'm sure had something to do with it), and had no trouble making friends or holding conversation with people by just being myself.
I'm not sure how mature the boarding, high school age, kids are in comparison to college ones... but I think you'll likely be fine. Act like a normal person and you'll find yourself surrounded by lots of normal friends, who will then proceed to bore the crap out of you with their conversations. Act like yourself and you'll probably have a lot fewer real friends (and, yes, you run the risk of getting screwed and meeting nobody who likes you... but I thought that risk worth taking. You really have to decide for yourself, though), but you'll actually enjoy hanging out and talking with them.
(hahaha... I promise I didn't see your avatar before writing that last sentence. It just worked out that way)
Waiting til 3am the day things are due is rough, though, haha. I've never even been that bad. If you want to get your work done, the best thing I've found is to get in the habit of doing it as soon as it's assigned. My freshman year, I tried this and by far had the least-stress year I've eveer had. I was about a week ahead on all my work at a given time, and played on average 2-3 hours of cards each day. As a more realistic goal (which I fell into as the years went on), I find that as long as I'm working when there's nothing else I'd actually want to be doing (friends were all working, or going to do something I didn't like, or whatever), there was/is always enough time to have as much fun as I want, and get all my work done in time. I just had to get rid of that stuff I sort of "did", but didn't really like... like playing RPGs on emulators and watching lots of youtube clips and stuff like that--the time-filler stuff that you wouldn't do if you had something better to do.
Honestly I think you'll be just fine. It's hard for me to think anything else, though, because my time away from home has been a huge asset to self-growth, and I got extremely lucky and landed in a dorm full of very sociable and equally-socially-inept people.
