In reply to Tony500: Hi, Im 41, in the last few year taken up Thai Kick Boxing (& teach it), become a higher level personal trainer, am fitter, stronger & faster then i have ever been in my life... if you put in the work & have the right mind set... never too late!
Im just starting climbing next week myself & whilst under no illusion as to how hard it is, don't expect to find it any harder than someone 20 years younger.
Just remember, if your mind is beaten your body stands little chance so never doubt yourself, set realistic targets (small steps) & train regularly.