Always a chance, but if you did not take at least 2 Honors or AP classes through Jr year, have no or limited leadership activities, and were below average on any part of your PFA (under 30 pushups or situps, 8+ minute mile), you will likely not be high enough on OML. However, many Brigades allow ROTC programs to "keep" scholarships turned down by students who later find out they're medically DQd or get into a service academy. The PMS can then award these scholarships (usually as conditional 3 year) to incoming students, which happened to 2 of my JROTC Cadets last year, and if you already met with the PMS and have demonstrated interest, you could be in the running. Otherwise, compete for one on campus; at that point sweat equity counts more than SAT score and many ROTC programs fill over half their contracts with on-campus scholarships.