Congratulations! Next step is to do it with something that has some recoil. Then you will know that you are concentrating really well.
My best group in 40 years of rifle shooting is a .207" 3-shot group at 100 yards with a custom 270 Winchester, shooting 110 Sierras over IMR-4350 powder for 3300 fps.
This past year I fired a .475" 3-shot group at 100 yards with my custom 35 Whelen Ackley Improved, shooting 250 gr Hornadys over PP 2000-MR powder for 2625 fps.
Both of these loads routinely shot sub 1" 5-shot groups, but occasionally would do better, when I was really on. Keep up the good work!