Magic Mouse 2

I have a magic mouse 2 and I rarely use it. When I plug it in and open it on my macbook to see the battery percentage, it's 0% so I disconnect it and let it continue charging. About 1 hour and 30 minutes later, I turned it on to check and saw that it was only 61% charged. I was worried because Apple devices usually don't charge that long. I went online and researched about the battery and if there was a problem with the battery due to my lack of use, and what I read confused me, they said that the bluetooth section show the remaining battery that i could use. Is it the % of my battery that has been charged or is it a sign that I need to replace a new battery? Like on an iPhone if the battery is below 80%, you have to replace the battery.

If Apple technical team or someone who has been like me reading this post, please help me, I'm quite worried because I really need to use it.

Appreciate for your help !