Hi jan4dday,
first of all, let me ask you one question, how's that you are in the last year of your undergraduate degree at the age of 19?
Regarding your question, I think you should do a bit of research about HEC, rather than rushing just because it's #1 in the rankings. Have you considered living in Paris? (BTW is not
exactly in Paris). Are you interested in learning French?
I am not sure, but when I was looking for the MSc in Management, I think it was compulsory for the first year. Where do you want to work upon graduation? If you study where you want to work afterward you will have more chances IMO.
In short, what I'm trying to tell you is that the rankings are a good start point, but you have to consider many other things as well.
Good luck.