New Zealand

So, over the summer i'm going on a road trip around new zealand with some friends from university. Now, none of us are in shape, but while we're there i'm starting a music video project. I want to lose weight in time for the trip, so that i feel more confident in front of the camera. I've got until June to lose at least two stone. Is it healthy to lose 2 stone in 5 months? Or should i set my sights lower? I'm currently 20 years old, 10st 10lb and 5ft 5in.

Any advice?