MacBook Pro 15 battery says: "Not Charging"

Okay so I am a complete noob with my Mac and I have no idea why that happened. My Mac is nothing near being new since it was my brothers long time ago.
Yesterday everything was fine while I was using it. I turned it off and later that day it didn't turn on until I plugged it in. Today I tried to turn it on again and it happened the same thing. The light on the adapter is green and the icon for the battery just says "Not Charging".
I really need some help since where I live there are no Apple Centers, nor Mac stores and nothing even similar.
Thank you very much to all of you and have an awesome day ^^

I'm not sure I completely understand your post regarding the battery, but it appears you're saying the battery is discharged and won't charge? It runs on AC power only? You stated the machine is not new but didn't say how old... It could be the battery failed and it may be that you need a replacement.

Regards.

First f all thanks for replying ^^
The battery is not completely discharged, it actually shows it has 18% but the computer only works on AC power.
I don't think it is a problem with a battery since the battery is new. My computer is 3 years old.

That might indicate a problem with the charging circuit itself rather than the battery. However, it could be something as simple as resetting the SMC which controls some aspects of charging. So I suggest you try that first before having the machine serviced.

Apple Portables: Resetting the System Management Controller (SMC)

Regards.