Met a girl at a party - What now??

[Guy]

So I met this girl from my school at a party.(at the very beginning) Me and my friend sat down on a table where she and her friends were sitting. She was quite drunk but not that much. She asked our names and wanted to add us on FB and such. We chatted some casual stuff with her - can't remember quite what tho. I noticed her leaning on me quite a lot. So after that we separated ways. Today, the morning after the party I added a new profile picture on FB and she "liked" it. Are these signs strong enough for her to be interested? Or was she just too drunk? Should i chat her up on FB? And how should I proceed then? Thanks! Ps. We're both 17. (18 this yr). Also, we're having a 2day cruise next weekend where she's coming too. Any advice appreciated! We didn't engage much but i think i'm crushing for her. I'm not very experienced in this so i'm asking for advice. Sorry for typos ;p