MacBook Pro

I have a late 2011 MacBook Pro, it will not turn on, when I plug the charger in sometimes it will turn green and stay green for awhile, other times it’s turns orange and stays orange, or the light will immediately shut off, none of this gives me enough of a charge. The lights on the side: when I press the button only the first light goes on and blinks for 5-10 seconds. When I try to power on, it’ll boot up for less then a minute and turn off. Before it did this, I was having charging issues but with a little adjusting of the charger and I was good. I checked the battery icon a week ago and it did say I will need to replace the battery but when I went into the settings it showed that I still had a lot of battery life left. The computer was working perfectly fine when I was able to get it to charge