Let me add to the voices of caution re being 18 and limiting your colleges choices. Acceptance at a federal service academy is a prestigious reward for a student's academic and other achievements. But so is an Ivy League or "public" Ivy college our university and many other quality institutions. You will get the absolute best military training at a federal academy, but you will also live in a regimented life style for four years that is unlike the actual military today. And - this does not mean you will become a quality commissioned officer. Whether you go to a federal service academy or a local open admission college, how successful you will be as a junior officer in charge of 32 young lives, depends on who you are not where you went to school. General Colin Powell, former Chief of Staff and Secretary of State, graduated from the City University of NY.
As for SMCs, they vary from large state research universities like Texas A&M and Virginia Tech with mix of big time college, hundreds of academic majors to choose from, and a military Corps of Cadets, to small college experiences like The Citadel and VMI, with a smaller basic offering of liberal arts, Engineering and STEM majors, combined with an intense and unique traditions. These traditions are based on a very structured experience that is unlike any military training you will go through in a military service. You need to decide what 4 year experience you think will best achieve your academic goals - your intended career - and will be fun. The latter is important because - those 4 years will be the best ones in most folks lives - you don't want to waste them. Visit and talk to students and cadets at these schools and read all you can about them.
For me - at the age of 18, I was convinced I wanted to be an Army Officer and enrolled in Army ROTC at The Citadel. By the end of my Junior year in college I was convinced I wanted to be an attorney and was applying to law schools. By my Senior year I was desperately seeking deferments from starting law school so I could first complete my Army active duty obligation as an ROTC contracted cadet. The obligation I committed to my Junior year to serve on active duty was one I felt honor bound to do, but could easily have cost me attendance at law schools of my choice. Best advice - ask questions, visit, read up on the history and traditions and culture of colleges you are interested in attending - and never ever limit your choices until you must.