Hi lightningad,
You can model in any scale. Size matters later on if you like to use dynamics, physically plausible lights, or even Depth of Field during camera work.
The ideal (in the old days) was to have the object three digits before the point and max three digits after it. (123.034). This is even today, my preferred modeling size.
You can set up the Project in any measurement you like and change that later on.
https://help.maxon.net/r23/en-us/index.html#html/DDOC-DOCUMENT_GROUP_PROJECTSETTINGS.html
If you use just the Scale object to do so, be clear about the Model v. Object Mode’s differences.
https://help.maxon.net/r23/en-us/index.html#html/5494.html?TocPath=Modes Menu|_____3
https://help.maxon.net/r23/en-us/index.html#html/5489.html
In any case, save your file before you do something you do the first time, or explore things with a simple object.
The final product should have the object’s Scale at 1; 1; 1 and not in something else.
All the best