What Should I Do?

The big question.

So i will be going to a big party for my mums 50th in a few weeks. Its going to be a big do which is ok with me, im looking forward to it! The problem is my mum's friends daughter will be coming. She is so cute!!! I think about her a lot I would love to ask her out but I just cant seem to do it! I have tried a few times but i make myself sick with worry and always look for the reasons not to do it! Any advice guys?? thanks, Dan :-)