So the distance is 71mm rather than the expected 75mm? If so, this isn't due to plastic shrinkage, it's simply too much to be that. Like Gigi said, print something smaller and verify on that. Say a 20x20mm square and see how that goes. I would suspect some sort of scaling error during export from Sketchup or an accidental scaling you made in Cura.
And just as a general piece of advice, if at all possible, try to avoid Sketchup. It's notorious for creating bad models that cause all kinds of problems.
The best way to see is to do a test design.
A plate with different holes and extruded forms with exact dimensions like ex. 1mm, 0.5mm etc,and print it.
Then make measurements.
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