8 metres is pretty safe really, and enough to give you a taste of what its like. I don't know why I don't dive anymore, after the effort of passing the 'exam' the desire faded away.
I have been down 30m and its a little different. You can get memorised with the bubbles and lose your crew if not careful.
My first dive was a wreck too, I don't know what the instructors were thinking.
Wow 30.metres, thats deep.... I thought 8 was perfect lol haha .. I'm not a big hero.in the water :)