Your cucumber is very close to being ready but it shouldn't have creases. A little more of a cylindrical shape should be gained in just a couple of days.
It would be best to not wait for any color change, although it may become somewhat glossy when it reaches that jus right stage. Don't worry about its prickly spines. New gardeners are sometimes surprised to see those. Supermarket cukes don't have them because they come off in washing and shipping. If you rub that cucumber under the kitchen faucet, the spines will come right off.
As has been said, inadequate pollination will keep some varieties from developing a good shape. The pictured cuke looks like it will be fine. A poorly developed blossom end can be ignored if there are several inches of cucumber above it to be enjoyed.
who has never cooked a cuke, not even in a canning jar with water, salt and vinegar
We are each other's harvest; we are each other's business; we are each other's magnitude and bond. ~ Gwendolyn Brooks