How good is Nemesis at Alton Towers?

I'm 14 and i've been on Space Mountain Mission 2, Rockin Roller Coaster and Indiana Jones at Disneyland Paris and they were brilliant especially Space Mountain and Rockin Roller Coaster. But I'm not sure if i'll be comfertable in a ride which is inverted because I have never been on a roller coaster which you are not in a train. Will I be scared or will I find it Brilliant? Please help