Great question
You asked, "is there a difference between PLC and OCS?"
That's a good question, and it's an important distinction.
Officer Candidate School is the actual military school, located at Brown Field at Marine Corps Base, Quantico, VA, where officer candidates are screened and evaluated to determine if they will be offered a commission. OCS is a place you go. Although not an exact analogy, it's sort of like Marine Corps officer "boot camp," in that prospective officers train at OCS in order
to become Marine officers.
PLC (Platoon Leaders Class) is one of several routes you can take that lead to a Marine commission. PLC is a commissioning
program. Other programs include: Marine Option Naval ROTC, U.S. Naval Academy, Officer Candidate Class [OCC], and programs for enlisted Marines.
Of these several programs, PLC and OCC are most alike in that they are both specifically designed as routes for "military unaffiliated" college students to earn a Marine Corps commission by attending OCS during summer breaks from college. Conversely, "military affiliated" students would be midshipmen in any of the many Naval ROTC units or at the U.S. Naval Academy.
To pursue PLC, you must be enrolled full-time at an accredited college or university, and, naturally, meet some sensible competitive selection standards (SAT/ACT scores, grades, background screening, physical fitness, physical health, etc.). As a prospect for PLC, you attend "civilian" college full time and take any major you choose. The PLC program "route" to a Marine commission also has two "sub-routes."
The first PLC option is called split-increment PLC and is open to college freshmen and sophomores. If you enroll in PLC as a freshman, you will attend OCS for six weeks in the summer between your freshman and sophomore year, and again for six weeks in the summer between your junior and senior year. Alternatively, if you enroll in PLC as a sophomore, you will attend OCS for six weeks in the summer between your sophomore and junior year, and then again the following summer between your junior and senior year. For split-increment PLC, the first summer session at OCS is called "junior" and the second summer session is called "senior." There's no duplication...the senior session builds upon junior session.
The second PLC option is PLC-Combined, and it's open to students who waited to enroll in -- or didn't discover -- PLC until their junior year in college. These PLC-Combined candidates attend OCS for a single ten week sessoin in the summer between their junior and senior year. A final "civilian commissioning route" worth highlighting is called OCC --Officer Candidate Class. This is a program for those who have already graduated from college, and OCC candidates attend a single ten week sesion at OCS, just like PLC-Combined candidates do. Unlike PLC-Combined candidate who finish OCS and then return to college for their senior year, OCC candidates who complete OCS and accept their commission go immediately on active duty.
When you're enrolled in PLC, there are no military activitites for you during the school year. Except for the summers you're at OCS, you're a "regular collge student."
I want to pick-up on something you stressed in your original post -- about not being absolutely sure just now that you want to serve in the military. That's okay. PLC acknowledges that commissioned service is "serious business," and it's important that only those who really want to be a Marine officer -- and have proven they can be one -- are offered a commission. PLC deliberately involves a mutual look at each other, and a mutually conscious decision after we both agree that you have "the stuff" to lead Marines.
When you enroll in PLC, your only commitment is to attend OCS. Again, depending upon when you enroll, this means attending the
first six week OCS session, or the one ten-week OCS session. If you determine from your experience at OCS that "the Marine Corps isn't for you," or if the Marine Corps decides that "you're not for us," then we amicably part ways and you continue life as a civilian. If, on the other hand, you complete OCS and both you and the Marine Corps want one another, you consciously decide during your senior year to accept your commission and become an active duty Marine Corps officer upon graduation from college.
As mentioned in the earlier post, you'll start your active service by attending The Basic School (TBS). If you enrolled in PLC with an "aviation guarantee," when you finish TBS you head off to Pensacola to start your flight training. The PLC (Aviation) guarantee is especially attractive because you know, at the time you first enroll in PLC, that you are guaranteed assignment to flight school, provided you accept your commission, complete TBS, and stay medically qualified for flight training. To affirm this last point, you receive an actual written guarantee -- a PLC Aviation service agreement -- at the time you first enroll in PLC. Now HOW you do at flight training is up to you and your performance in flight training ultimately determines if you will become an aviator. But PLC (Aviation) guarantees that you will be given a shot at flight school, again, provided you complete OCS, finish your degree, accept your commission, and finish TBS.
You can learn more about the PLC program, and gain some deeper insights into service as a Marine officer, from the Marine Corps' official officer programs site:
www.marineofficer.com.
Good luck. Semper Fi.