C Drive

I have a 120 GB SSD C drive with 111 GB's full but when I go into the C drive to see how many GB's it's 81 GB's? Windows has 47 GB and Users has 25 GB and I took a look at the data but I can't figure out what to do but I don't think my C drive should be this full and I'm the only one using the computer and I have had it for 3 years so any suggestions?

You can use something like WinDirStat to see what's sucking up your space, it even gives you a graphical representation of the data.

https://windirstat.net/

Your drive also may be partitioned, which you can observe in diskmgmt.msc