There is a danger in pursuing the highest levels of education.
It is not, as a few antagonistic atheists suppose, that doing so will teach you to think, and that thought is incompatible with faith. In point of fact, some of the brightest people throughout European and American history, even recently, have been Christians. Some of them have even become Christians, not simply grown up with it. (Indeed, I wish more people, both Christians and others, would learn to think better.)
Nor is the danger, as some Christians suppose, that all Christians pursuing graduate education will be brain-washed by professors who are antagonistic atheists out to destroy their students’ faith. No doubt there are such professors, but graduate students are supposed to think critically about what they hear from all sources, and many advisers give their students a fair degree of latitude to disagree with them (in certain areas). Historically, Christians have learned a lot from studying with non-Christians, such as the fourth-century author John Chrysostom from the pagan Libanius. And of course, Christians worried about such brain-washing can pursue graduate study at confessional Christian schools. While I have known people who have left Christianity while pursuing graduate degrees, I have also known Christians whose faith grew and flourished even in very secular environments.
Nor is the danger that “bad company corrupts good character” (1 Cor. 15:33, quoting the pagan poet Menander). While this is certainly true, in general academics are no more immoral than can be found in any bar, coffee-house, movie theater, sports stadium, large corporation, or other place where people gather. The apostle Paul made clear that Christians were not to shun the presence of all non-Christians (1 Cor. 5:9-11).