With respect to your future plans to attend an M-7 MBA program, you do not need to worry about grade deflation at Princeton. Your post undergraduate work experience and your GMAT score will be more important in the admissions process assuming that your undergraduate GPA exceeds 3.40.
The most recent M-7 admit rates are:
Stanford GBS–6.7%
MIT–Sloan–11.5%
Harvard–12%
Columbia Business School–19.1%
UPenn–Wharton–22%
Chicago–Booth–22.5%
Northwestern–Kellogg–26%
Based on your SCEA acceptance to Princeton University for undergraduate school, you should be able to be a very competitive applicant for most M-7 MBA programs.