Birthday :( help ?!!!!!!!!?

Im going to be 15 soon and my mum said I can't do anything, all I wanted to do is have a meal out with my family . I know I probably sound like a spoiled brat but.. my mum bought my 13 year old sister a camera which was fairly expensive and she has a bbq( we.didn't have a bbq before so they had to go out and buy one for a 100 and something quid and my mum and dad always go at for.their birthdays. I just think its unfair I don't get to do anything and I'm not allowed to have the equal amount of money that my sisters camera cost ( if that makes sence ) . What should I do ??