DON'T go to Paris..
It's cliched and so many couples I know who went there broke up shortly afterwards because everyone has high expectations of it being a romantic, perfect trip and it never figures out that way..
Try Italy. My boyfriend and I stayed in a lovely cheap b&b by the sea called Viareggio and it was very reasonable and perfect.
I was only 15 at the time as well but got on just fine!
Also, if you're looking to book anywhere, check the hotel out on tripadvisor as it gives honest ratings from previous stayers.
Good luck!