After exporting your project go the folder and open Config.XML and Config.json
in Config.XML you will find something like this:
<preference name="android-minSdkVersion" value="19" />
Change the number for this --> value="19" --> to what you want,
next go to Config.json and look for ( under Android ) :
and same thing do here, change it as well, but the number must be the same as before.
PS. be sure to check what google minsdkversion because I remember they require now 21 or 23 not sure.
Good luck hope this help