It's certainly not too late to apply to a regional. A lot of foreign students train in the USA. What you'll need to determine is working rights, and whether you can secure employment without citizenship. This depends on your status (and possibly your relationship with your now-girlfriend). I've known a number of Dutch, british, French, German, and other European pilots who have come to the USA and worked. Before you get too mired in the cost and financing, find out what your work options will be.