I have changed a command (verbal) and/or signal for a particular dog. This has been especially true as you get into the utility signal exercise. I experiment with the particular dog and find which one seems to work best FOR THAT ONE...
Example...
With Gracie, I used a downward motion to signal her to go into a down--but Chubbs didn't seem to respond as well to that, so I changed it to a arm raised above my head. I also switched hands for the "sit" signal and turned my hand outward more (she was getting confused between the come & sit signals)
I teach my dogs both verbal & signals and find which one works best in whatever exercise. Then I gradually fade out one or the other for the things that only allow a single command or signal in the ring. Gabe seems to respond best to signals and I started using only signals for him pretty early on...but I like to throw in some practice with verbal, too, in case he happens to get distracted by something in the ring and might miss a signal.
That's great that you're getting started early with training...I think it's so important that puppies "learn to learn"...and they'll soak up everything you throw at them! If you keep it fun & rewarding, they'll love adding vocabulary, new tricks or skills!