Nowt wrong with taking a gap year . . .
However, at 17, you really should be putting your education and long term prospects before 'love'. I don't doubt that you really care for your boyfriend, and it is very possible that you genuinely love him (as opposed to having some rose-tinted lust). But really, if you guys are good together, you will survive university. And if you don'[t survive university, how do you expect to survive the other trials of life? The adult world isn't all about spending lots of time with your sweetheart. You can't refuse to get a job because you are worried that you won't be able to see him four times a week. I was in a LDR for months, and only able to see my other half once a week, if that. Not the worst case scenario, but it shows that people can survive on moderate contact.
If you take a gap-year, and are still with him and love him by the end of that year, is it really going to make your going any easier? The more used to being together you are, the more difficult it will be to move away. Your relationship sounds thoroughly self-indulgent. Life isn't like that. The sooner you realise and have the balls to make difficult decisions, the better chance you have of emotionally surviving.