I didn't realize how much variance there can be with Cuban cigars. Every time I had a bad one I thought there was a problem with the humidity/temp in my humidor. I became kind of obsessive about it, to the point that it detracted from the hobby and it wasn't making the cigars smoke any better.
Also aged stock isn't necessarily better, it's just different. Buying a newer box and seeing how it evolves can be part of the fun and gives you an idea how long you prefer to let them age.
As others have mentioned, try lots of singles as first. I prefer to go deep on regular production i really like as opposed to limited editions/regionals.