It is only going to get better. That's a great goal to shoot for and you can be there before you know it. When you hear him say holy s**t under his breath as you pull up- next to him, without breathing hard will make it all worth it.
It's good that you are riding the hills and flats, they both have something different to offer and will compliment each other in your overall riding performance. Oh yea, that buzz feeling your getting is a clear sign that you hit a level in cycling where there is no turning back, enjoy the journey.