My tablet won't turn on.

My tablet says it has 100% of battery. But it won't turn on.

It was glitching when the battery was lower than 35%. Then it started to reboot. So I read that it could be the battery connector that could be a little loose. So I opened up the back of the tablet, disconnected and connected it again. It solved the glitching problem. Then a few days later, the battery started to run out faster. It would also reboot. But while it plugged in, it would work ok.

Now, when I plug it in, it says 100% but it won't turn on.

Could it be time to a battery replacement?

Thank you.