At this point do not enlist or even talk to a recruiter. Do not believe anything a recruiter says. Some of them tell some real whoppers.
Focus on doing well in school and on your EC's. Talk with your school guidance counselor specifically about your situation. Apply to the Academy and also apply to other schools. Consider applying for ROTC, even though AFROTC is not a guaranteed path to commission. Look for schools that are generous with scholarships and financial aid. Out of state schools are sometimes very generous. Smaller, unknowns, are sometimes generous. Use your gpa and test scores to find schools that match you. You will need to spend some time researching. If you are competitive for the Academy you may be able to find a college willing to give you a full ride or mostly full ride or at least full tuition. Save enlisting as your last resort.
I get your concerns. I have seen those that enlist and leave immediately after graduation. Some don't leave for few months. I also know of a kid that didn't leave until 1.5 years after graduation because it kept getting pushed back. Hold off for now talking with the recruiter.
Make a plan for what you want to do. Give yourself several options. Make a plan for what it will take to get you where you want to be. Work your plan. Have multiple plans/options i.e. best case scenario, worst case scenario, and at least something or multiple somethings in between. Seek out help from friends, family, teachers, coaches, co-workers, neighbors, and sometimes even strangers or anyone you think may be in a position to help you or be willing to help you. Make your plan. Work your plan. Do not give up. Go after what you want.
If you do go the path of enlisting, remember if a recruiter promises you something it must be in the contract they want you to sign. Read the contract before signing anything. If what you were promised is not printed there then do not sign. If it is not in the contract it won't happen.
Since you mentioned loadmaster here is a story of a loadmaster. I had a friend that was an Air Force loadmaster. He enlisted at 17. He went to Vietnam. He came home. He loved flying. He ended up getting his bachelors. He chose to remain enlisted and did not go the officer route because he didn't want to give up flying. He would have been flying a desk. Between active duty and the reserves he went all over. We were always seeing him on the news anytime there was anything going on in the world. He was retired from the military after over 30+ years. He passed away a few months ago. He was buried in a military cemetery with full honors. At his funeral there were at least 5 very low fly overs. He was buried not far from where his old unit was. Most people are lucky to get one fly over. The crew from his old unit sent him off in style. It was pretty amazing.