Relax...take a deep breath...everything is fine...
Yes, there is wine-tasting on the 4-night Wonder. On our cruise, it was on Wednesday - the day at sea. I believe the time was late afternoon - I'm thinking it was about 3:30'ish. The cost was $12, and well worth it.
You do need to have a ticket for this event, which you can get at Guest Services.
I really enjoyed this. It is truly amazing what they can do to a bottle of champagne!