If you are trying to provide peer counseling or academic counseling, the most useful thing to do is to get a copy of the college's Math curriculum. This way, the newly-enrolled student will get a chance to see exactly what is expected of students as they enroll, and what are the requirements to pass the course with a passing grade, which is the ultimate goal.
Since the student may be excited to be crossing the threshold to college life, a suggestion that may very well work is to NOT talk about Math as a potential obstacle. Instead, show the curriculum, samples of different syllabi from a diversity of professors, and even direct the student to the college website to determine which professors have a teaching style that may help the student succeed.
Encourage the student to speak to the instructors, to ask questions, and to take notes as to the personality traits, teaching styles, and academic expectations. Students can actually "preview" teachers by going as auditors. All that they have to do is ask the professor permission to be a listener for one lesson, and to be honest with the instructor by telling him/her that the reason behind wanting to listen in is to choose an instructor that may be most helpful for Math needs. Some instructors might actually appreciate knowing before hand that a student may need help; other instructors (those who really care for their students) may even recommend a specific professor to the student.
Realistically, what we think to be a big hurdle in our opinion may not be a big hurdle to someone else. As professors, we have had incredible surprises with students who happen to find "their call" precisely when the hurdle becomes big; and right when they think that they are going to fail...they succeed! Be sure to never talk about hurdles and obstacles; college is a stressful change of life as it is. Instead, show the student the freedoms that one can have as a college student when we are able to walk around campus, observe the talent that surrounds us, and being able to speak to an instructor without shame to ask for help. That is their job, and that is what they are intended to be there for in the first place.