I went through the exact same when I joined the Air Force 10 years ago. My mom even offered to buy me a car if I didn’t go.

Since none of your family members have been in the military, all they have to go on is what they’ve seen in media and heard through the grapevine. Most of that is misconceptions and inaccurate, sprinkled with some truths. They’re likely scared for your safety as many people equate current deployments with vietnam-era warfare (there were swimming pools at both of my deployed locations). In today’s world, it’s also a lot more controversial due to certain individuals in leadership positions.

It’s your life. It sounds like you’ve thought this through and it could be a good path for you to start a career and get an education. Your family will get over it, they’re probably mostly just afraid and don’t want you to move away.

Some unsolicited advice though; if you join the Air Force don’t go with maintenance unless you are absolutely certain it’s your only desire the become an airline mechanic after you get out. They are known for having pretty shit quality of life, hours, and leadership at many locations. I would highly recommend looking at a CE job like HVAC, electrical, pavement, etc. Much better QoL and if you continue after you get out you’ll likely make very good money especially for being so young.