I hope so lol
Yes, after orientation you can change your major. Before you could change your major a bunch of times, but I think in the last year they changed it to 1-2 times no questions asked. Afterwards, I think you have to apply for a major change. When you go to orientation and to register for your classes, ask your adviser about a major change. Also as an fyi, I would attempt no more than 12 units your first semester at Tech. There will be some adjustment and having 12 units makes it more manageable.
Every admitted freshman (but not transfer students) gets 1 unrestricted major change AFTER the withdrawal deadline for their first semester, so yes, you can use this change to switch to any major Tech offers, but not before you register and enroll for your first semester courses. After the first change, you have to go through the regular major change procedures governed by each school.
12 units is very light at GaTech, because freshman have to take health, and everyone gets an A in that, and have to take a resume writing /interviewing class and every one gets an A in that, and all freshman take English 1 and/or English 2 if they place out of English 1, and everyone gets an A in that class. Linear algebra is usually the other class one takes in freshman year. If you take Honors Linear algebra, you will work a lot but no degree program requires honors math, its always optional at GaTech. . If you have to take Calculus 1 and 2,in freshman year, that will be harder than regular linear algebra. Calculus 3 is arguably the hardest class in freshman year. Freshman also take a social science class, all are very easy to get As. So the difficulty of freshman year will depend on–
Your preparation
How many math classes you take at once, one at a time may be best
How many easy humanities and social science classes you take in freshman year.
Its best to spread out some of the social science requirements. There is an ethics requirement in most majors as well, which is another easy A.