Since I'm 17 years old and will be turning 18 in 7 months, if I was recently offered a job, can my parents legally make me reject the job offer?

It really depends on the state in which you live but typically, parents must consent to the employment of children below the age of fourteen. Some states also require work permits for minors of any age.  But parental consent may also be required for older teens, but often permission will be implied in the absence of objection.  So what does that mean?  If they want to object to the employment they can.  Try and speak with them rationally and present a case in an "adult like" manner: weighing the pros and cons and showing how you plan to manage the job and school.  Maybe that will help.  Good luck.