I think it depends on lifestyle.
If one is a student, one at school - their lives will be totally different and in my experience incompatible. Student life tends to need a student partner - schoolwork can't keep up with student drinking/partying!
If they are both working, difference wont be great at all and the age gap won't matter.
School and working might suggest different clashes of interest too, thought I've seen it work in the past.
What are the situations of the people involved OP?