If you love your job you will never work a day in your life. I am sorry to say but once your 18 your mom has NO say in your career path.
Theres this job i want to work at its not dangerous its safe but my mom is the opposite i tryed to tell her. But she won't listen to me?
Well if your mum has concerns about safety, it makes me wonder what the job is?
It's hard to defend or disagree with her thoughts about the topic because you've provided no details. Perhaps there are dangers out there in the real world that, because of your age, you simply aren't prepared for quite yet. THAT may be the dangers she is referring to.
Trust your mom, she love you.