It does not matter much if you are an average student as it is a relative term. You should always aim for the best B Schools of the country as they offer you the best exposure to the industry and academics and you learn from your peers, Faculty, industry experts and others. If you talk about placements, even average placements in top B Schools are higher than the highest packages of average B Schools.

Also there are many students who might be average till now but after joining they shine as they become very interested in the subjects taught as it is a quite practical course.

Prepare well and hope for the best!