I’d say the most popular place for wakeboarding in Central Oregon is Lake Billy Chinook. It’s strikingly beautiful and large. Three rivers come together and are dammed into a fantastic waterway for boating.
Another popular spot is Cultus Lake. Both Billy Chinook and Cultus are about the same accessibility from Bend, but they are vastly different in terms of surroundings. Cultus is surrounded by forested mountains while Billy is in a high desert rimrock canyon. Given the time of your visit, I’d choose Billy Chinook. Cultus can be colder as it’s at a higher elevation.
Plus, Billy is simply bigger and, in my opinion, more fun to traverse than Cultus. Have fun!