Posters have hit main points. Like athletics and AROTC , work and AROTC can be done, just takes willingness to compromise a little by coaches and employers, and hard work by you. DS worked p/t on campus with AROTC scholarship. Remember if you are on scholarship stipend is not taxable but your P/T income and summer AROTC training monies are; along with college monies you get for housing , above tuition monies.
May be reading too much into this but an employer (in restaurant business) that will only hire you for summer if you agree to work part-time as you begin first year college, and doing AROTC seems like they are indicating they are not too concerned about your priorities, such as education and future career. Understand it is their business and doing what is best for them, but you need to do what is best for you. Just saying. Good luck!