I like rock climbing but I am new, do you know if it's dangerous? 
Anything that requires to climb high in the air, up down, and across natural rock formations could be dangerous
Are there different skill levels?
rock climbers do not usually climb back down the route, or "downclimb", especially on the larger multiple pitch class III–IV, or multi-day grade IV–VI climbs. 
Rock climbing is a physically and mentally demanding sport, one that often tests a climber's strength, endurance, agility and balance along with mental control. It can be a dangerous activity and knowledge of proper climbing techniques and use of specialized climbing equipment is crucial for the safe completion of routes.
Because of the wide range
grade 5.7 or 5.8), and later Jones became so proficient on it he could go up the crack and down an easy chimney nearby in seven minutes. This was a benchmark climb, perhaps as difficult – though not as dangerous – as anything being done in Saxony at that time. Jones developed the forerunner of the currently used British adjectival grading system for rock climbs.
In 1897 O. G. Jones published, with George Abraham, his classic "Rock Climbing in the English Lake District"; Jones's exuberant style did