You answered your own question....."
College volleyball is too intense to play a position you don't like (unless the team has an injury or a specific need which arrises during the season). If you like opposite better, then play that position. It is not like you are going from a Fab 50 Outside Hitter to learning to set because it is 'fun'.
Pursue college as an Opposite because you are already getting recruited for that position, even though you also played middle.
Trust your instincts and your instinct is telling you Opposite is for you!