Each of the SMCs have their particular strengths. Visit the various schools if you can, and do your own research. Between the sundry search engines, YouTube, and the host of specialized sites relating to colleges (College confidential, Unigo, College data, Student Prowler, etc.), you can learn a lot. Contact the various schools; I believe you'll find most are pretty open and forthcoming relating to their respective programs.
I didn't attend an SMC and I wasn't in the military. That said, I've been involved in aspect of public safety for the past (OUCH) 40 years, since I was 17. Man that stung! Anyway, as a cop, as a volunteer firefighter, as an EMT, and for the past 25+ years as a federal prosecutor, I do feel qualified to offer an opinion about law school and criminal justice as those subjects are something I do know a bit about. 25 going on 26 years sigh.
As for law school, it requires a four year degree. Unlike our brethren in the medical field, most law schools really don't care what you majored in. I've known folks with engineering backgrounds, French majors, accounting majors, criminal justice majors, English and Poly Sci majors - well, you get the idea. Law school is about getting you to "think like a lawyer", mostly because law changes from day to day, and is different from state to state (think wills, estate, what is a marriage, divorce laws, contract laws, what constitutes a confession, etc.) - in marked contradistinction to a femur which remains the thighbone wherever you are.
There are thousands of law enforcement agencies in the United States, from 1 or 2 person "departments" to the thousands in the LAPD or NYPD, or the Department of Homeland Security in the federal system. They all have their own hiring requirements. Some want a high school diploma, some want an Associate’s degree, and some want a bachelor's degree. Some of the "boutique" agencies have some specialized requirements (think of wildlife sciences for Fish and Game type agencies, accounting majors for IRS Criminal Investigations, etc.). That said, most of the ones that require a bachelor’s degree don't care what you major in, the degree itself is the "filter". I worked with one FBI agent who had a PhD from MIT in aeronautical engineering, and Bureau agents who didn't. Some FBI and other feds have law degrees, most don't.
This isn't to suggest that you don't major in criminal justice - you find the art that speaks to you. You find the school that speaks to you. I've worked with lots of JAGs, some on active duty when an investigation involved military equities, some as reservists or Guard members in one or another of the offices, some as co-workers who had been JAGs. I worked with lawyers who were, or who have been, Air Force JAGs, Army JAGs, Navy JAGs, Marine JAGs, and Coast Guard JAGs. Their undergraduate degrees, and the institutions they got them from, are as varied as the country is large. To go to law school, do well as an undergraduate in a school you are comfortable in, and which you can afford. Law school is becoming more and more expensive.
If you are still in high school - have some plans but take a cue some of the great military theorists. No plan survives the first contact with the enemy; and to be victorious, know not only your enemy (think goal) but also yourself. For a prospective college student – expect to change your mind. Life happens, plans change. Get a good education so that you’ll have options as the time approaches to make decisions about careers, about possible graduate school paths, about finding your way and your dream.
This is an exciting, once in a lifetime, time of your life. I wish you the very best.