If you need (or want) a bigger mouse cursor on your Mac it is very easy to do. And changing the size on your account doesn’t change it on other accounts that may exist on your Mac.
Select Apple Menu > System Preferences > Universal Access > Mouse & Trackpad tab.
The Mouse & Trackpad tab looks like this.
Under “For difficulties seeing the cursor” you can set the size of the mouse cursor using click and drag. It can get quite large if you need it to as seen in this example.
The change takes place immediately. One note, the larger cursors will look a little fuzzy around the edges because they are just magnified versions of the smaller versions, but if you need or want the larger size, that probably won’t matter.
Obviously you can change to another size at any time by repeating these steps.