My son goes to umd and he is also a very shy person and always had trouble with making friends. The good news is that it IS possible to find a group of friends at umd! And, being from Maryland, AND from a very large Maryland High school, he DID see some people from his high school at UMD but I believe he would tell you it was different - and that one can “start over” easily there - bc its such a huge school with so many people - you are NOT limited to those people from your high school. You could go all 4 years without having to befriend them at all if you don’t want to. (Or you can).
I can tell you is that umd is very large but one can definitely get a small school feel, especially if you are in one of the living and learning communities. There are some which focus on coimputer sciences but there are all of the ones in the scholars community which is interdisciplinary. If you got invited into one of the living and learning communities at umd I would highly recommend joining it.
Also - turtle camp gives you an opportunity to get to know people in the summer before school even starts. I recommend signing up for the turtle camp you are interested in. My son did the bike trip on the c&o canal. I think he was too late to join the kayaking one. They have several choices. Its a great program. You’ll start to get to know other people. There is one where you stay on campus and take day trips and if you do that one - you’ll get to know the campus better - before everyone else moves onto campus.
The other news, which you may already know, is that the computer science department is VERY GOOD but he was just telling me yesterday that it is NOT an easy program at all. He knows computer science majors who struggle with their computer science classes. HE is NOT a computer science major (he is a physics major), but he came into college having had a LOT of high level computer science classes in a computer science magnet high school. So it sounds like you are trying to decide between 2 very different levels of computer science education - so I would say it depends on what you are looking for in terms of your computer science education.
It sounds like you need to determine which is more important to you - what you want out of college… the social life like the one at Taylor University or the computer science education at umd. If the setting/social life of Taylor is what you want - you can always attend boot camps for computer science later on. Computer science is one of those careers where you will have to do a lot of self study for the rest of your life.
hth