Hi gmateurope2020,
Based on your years of work experience in finance, GMAT score, UG GPA, and Norwegian nationality you could be competitive for HBS, GSB, and Wharton. The fact that you're not from a known school and not from a "feeder" firm can be overcome by a stellar application. What you need to do is really differentiate yourself from all the other applicants with finance backgrounds, especially the ones from bigger name firms and prestigious schools. Through your application, you need to exhibit top leadership skills, wow the adcom with your achievements, and make a case as to why you cannot achieve your long term goals without an MBA. They want to educate those who need the education, so you will need to think through how the MBA is a crucial part of your future success. You state that you want to go back to the same firm, and if not the same firm at least in the same industry. This is a hard justification for the degree since you can advance without it, as evidenced by the fact that you're contemplating waiting to apply after getting a promotion.
Regarding timing, when you're going to be 6 years out by the time you enter school, I wouldn't wait to apply. Too much experience can also work against you, for the same reason that you may not really need the degree at the point.
Feel free to contact us at
Admissionado.com if you would like a free consultation. With more information about your background we can offer more insights on your chances with your target schools.
Best,
Cindy