First of all, GTK+ (Gnome's GUI toolkit) uses larger-sized widgets relative to Windows. Secondly, Linux Mint -- as well as most other distros -- employs large fonts (10 px @ 96 dpi ) in its default themes whereas Windows is set to use 8 px fonts @ 96 dpi (except for title bars, 10 px) by default.
So there are three ways to mitigate your complaint:
1. Reduce the size of fonts in Control Center > Appearance > Fonts tab.
2. Change the appearance theme.
3. Combination of both.