Hi
@kissbaby3, no need to worry
With an ethernet cable your pc is in direct connection with your router so is unlikely to be intercepted.
Wifi though, broadcasts in every direction and needs a security password to connect to your router.
If you have wifi on a laptop, tablet or smartfone, take a look at all the wifi signals you "could" connect to. All your neighbours connections will be visible and if you had their password you could connect to their router lol.
Anyway, for now don't worry. You only need security if you are using wifi