I'm thinking stress - you're feeling anxious and not entirely in control, worried about making a mistake, worried about going down, worried about every little thing. Relax, take it slow and enjoy yourself - soon you'll feel like you did when you were a kid when riding a bike was effortless and the bike felt like it was part of your body.
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"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey