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Question
I have never rock climed is it hard to do?

Answer
The answer is yes and no.  Yes it is hard if you step up and try to do it without any instruction. No it is not hard to climb if you learn some basic ways to place your hands and feet.

Of course climbs are rated according to difficulty and there is much more to climbing than moving up the rock. There is equipment knowledge, rope handling, belying, lead climbing, placing protection from falls and more.  So the answer to your question is complex. Climbing is no more difficult to learn than any other sport you learn rules, techniques and practice them. Some people like in other sports are better than others, but all can have success and fun.