Thank you dhoti_prashad and josedai from prompt reply. I got my GC through employment basis with US degree. As I asked earlier, is it true that I will get a priority date once I file the I-130? Is there anything that I need to do in Nepal for this process?

Another question I have is, she is planning to apply for a non-immigrant visa after our marriage. She has to take some educational exam in the US (she will be taking some exams in Nepal also). After our marriage, is it true that she will have difficulty to get visa because I am a GC holder? Is it a good idea to postponed our marriage just because she cannot get visa because I hold a GC?