I do think that college exposes you to a greater variety of people and many do not consider the possibility until they get that exposure.
Based on people I've talked to through the years and a fair amount of reading on the subject, well over half of LGBT's realized their sexual orientation during middle school and high school. About a quarter between graduating high school and their mid-twenties (college years). The rest either before middle school or after their mid-twenties.
Unless you can propose a covariance between being gay and making the decision to attend college.
A 2013 Pew Research social trends study of LGBT Americans showed LGBT were 5% more likely to go to college than the general populace.