Should i let my 17 year old daughter to malia with friends and no adult?

My daughter wants to go to malia with 5 guys 5 girls in the summer> i dont know any of the friends that shes going with. one of them has a mum who lives in malia. she is trust worthy but last year i have had to pick her up from 2 parties where she has been sick from drinking too much, but hasnt been sick since and says shes learnt her lesson. i fear shes not streetwise enough. should i let her go?