If OP gets down on the drops with decent quality kit and good tires like Continental GP5000, his speed will bump up 3 mph on the new bike. The position making most of the gains. Keeping riding and the engine gets stronger and then riding with a group and suddenly 20 mph average will be routine.
Just make sure you get enough rest to recover from rides. It is easy to have so much fun that you can burn yourself out and then it is no fun. Moderation and consistency is key