There aren't many students who seriously think when it comes to their own career.
ご質問ありがとうございます。
「自分のキャリアについて真剣に考える学生は少ない」は英語で「There aren't many students who seriously think when it comes to their own career.」と言います。
上記の英文とほぼ一緒ですが、もう少しコンテキストで「若い頃は、異性や友達との付き合いの方が興味があるので、自分のキャリアについて真剣に考える学生なんて少ないんじゃないかな」と言いたいなら、そうすると、「When people are young and still students, they aren't many who seriously think when it comes to their own career because they would prefer to spend time with their friends and the opposite sex.」になります。
ご参考になれば幸いです。