You're young (in fact way to young to be thinking about this surgery), so he's going to be over-protective and think you're generally naive. Deal with it, it's what parents do. (I'm surprised it's your mom that is supportive... from my experience it was my mom who possed the biggest problem).
Don't bank on doing it after college BTW. Life doesn't work that way. Honestly, depending on your major/career, I wouldn't take a year long break after college. Seems off to employers. Also if you have to worry about loans, kiss that time frame goodbye. I'd rather save up for college and/or pay off my student loan debt first (would your parents really want you to focus your savings on needless surgery when it can be used to fund your studies?!): especially at your height (then again I wouldn't want LL at it...).
But if you want some more advice on it, don't talk to him about LL until you're actually done with college. It's stupid to talk about it when you're so far off and you should be concentrating your time on your studies; which will produce the income you need to go to a good doctor. In relation to that...
It does feel like you're not really realistic and rushing into it... which from past records... is pretty much the biggest downfall of many LLers: they cut corners, wanting to take the easy, cheap route, and end up with bad outcomes...
My 2 cents