Flashing Question Mark, not Mac HD in disk utility

Hi everyone :) I have a MacBook Air probably 5 or 6 years old. I have had this problem for some time where if I turn on my MacBook I get a flashing question mark. I usually just open disk utility and somehow boot it into safemode. I tried to do it today but it won’t let me boot into safe mode. So I decided to watch some YouTube videos and everyone said I needed to erase Macintosh HD. Macintosh HD isn’t an option in my Disk Utility. The only option I have is “disk 0” and under it “OS X System”. Is it time I just bought a new MacBook?

im not the best tech person so if someone could help me by explaining in really plain English I would so much appreciate it. I also live too far away from an Apple store to take the laptop in!