The concept of opportunity cost has nothing to do with the "average individual" it is the cost of the "next best alternative usually forgone". I did not go to college, during most of my "college years" (18-22) I worked a total of 50-80 hours at as many 3 different jobs. That was my next best alternative. I still work 50-70 hours, between different jobs and businesses and transitioned from working class to upper middle class. In retrospect, I can see, for me, the opportunity cost of attending college would have been very high...
I agree, individuals need to evaluate the opportunity costs for themselves based on their own circumstances.
For a policy discussion, the average or median is relevant; and you are an outlier. The median income for 25-34 with just a high school education was $25K in 2009[1].Average work week is internationally around 40 for 25-34 year olds (post-industrial) [2]