Heading over to her house for the weekend, will i ask her then?

there's this girl i really like. she lives a good distance away but i get to see her regularly enough. this friday i'm going to be heading over and staying at her house for the weekend. she's holding a party for herself and her friends because they've just finished their exams and she invited me down aswell. we get on really well and we keep in touch over skype and talk for at least an hour most nights. i really like this girl, and i'm gonna ask her out. i just don't know whether i'll ask her while i'm over friday or the next time i'm down. i haven't been over in ages but its the start of the summer so i'll be able to see her a lot more. so will i ask her now at a party, but after not seeing her for quite a while in person or next time after the whole 'not seen you in ages' thing wears off if you catch my meaning. to be perfectly honest i think i should wait but i don't know whether this is just me procrastinating again.