Congratulations Sara Fanta,
You will enjoy working for Virgin its a fun culture and altough it can be tiring at times, we generally do have a good time.... With respect to overnights, I would not worry too much, it will take them some time before they ever phased them out, with expansion as it is, I can only see them increasing overnights to cope with the parking off aircrafts in ports other than MEL, SYD, BSN...
In regards to training, all the advice I can say is take LOTS of vitamins, prepare your body for stress as that is a natural reaction... You just have to focus for the 5 weeks and keep your head in the books.. They will tell you all about it, but basically you have to know everything WORD FOR WORD... And yes at the start it all seems rather scary and you think you will never learn it, but trust me the trainers drill it into your head and you will sleep and eat commands, equipment, SOP etc.... Most importantly dont forget to try and have some fun in training and it is part of the job you will always remember and you will make some friends for life out of it..... Also get your camera ready and take LOTS of pics...
Good luck and if you have any questions please don't hesitate to ask, more than happy to help..
Regards SocialFlyer