I think you need to test with a few different ones before buying. I'm not sure, but I believe the CZ 75DB goes from double action to single like most others with a decocker. Learning to get a fast second shot can be difficult for some people. ( I blew the second shot in a panic situation.) BTW, decocking, but not also using the safety is the same as using a DA revolver or using a Glock. And the trigger pulls for the Glock and the revolver are identical pull after pull.
Like one other here, I think you ought to get a 22LR. Use it for practice and getting used to a DA pull and the sight picture, not to mention just getting used to shooting and hearing the shots. THEN, look for a proper SD handgun. The 22 will be easier on your wallet and just maybe, while at a range, you can get to fire somebody else's firearm in a defferent calibur/configuration.
Member, GoA, NRA-ILA, SAF, NRA Life Member