Third year CS Tech student here! Congrats on obtaining admission to the best university in the world 
People are defiantly more outgoing then you would think! we have a large amount of social greek organizations and other activities throughout the campus that really brings out the social/friendly students. Yes, you will have some awkward students in your classes but there will be awkward students everywhere. If you are a social kid, you won’t have issues finding social friends. I believe its those who don’t try to find friends outside the classroom one way or another that have trouble grabbing a friend group if you decide not to go greek. Class really depends on your major! As a CS student, i notice that class is not about memorizing stuff that much. There is a club almost on anything you want here at Tech that interest you! As a greek student, I have time to do well in classes, grab some sleep, and still be social on Fridays and the weekends. It is super important to not loose your social time here at tech because you will go nuts if you try to study all the freaking time. If your interested in greek, at least try it out 
From my understanding, there are pianos for students in the music center or other places around campus to use. I have not heard about pianos in dorms though. Let me know if you have any other questions!!