Sarah
You have reached the next level of 3D printing!.. printing interconnecting parts.
When making parts to fit into other parts the caution is not to make them exact.
Meaning that when you make 1/32" hole in something the male part that fits in should be less than the 1/32 hole diameter; a 1/32" diameter post will not fit into a 1/32" hole because the both dimensions are exact. Because the 3D laser printer's printing is so precise.