I think of it this way - when I'm riding "road" I'm a serious adult cyclist, concious of my surroundings, intent on training...

When I riding my mountain bike, I'm 10 years old and riding and jumping and whooping and having a ball. I love to mountain bike! Plus there's the added beauty of trails, trees, birds, butterflies, wildflowes, wild life etc. Enjoy, take your time and learn some skills.