I think you can move from totally unhealthy diet to a reasonable diet very quickly, and so get your test numbers down to good levels early on, but then you have to settle in for the long haul.
I was lucky and diagnosed at quite an early stage. I got my numbers down in the first few weeks but I wasn't able to sustain the effort for the longer term.
Since then, I've been using my meter to find out what various foods do to me and how much of a problem slipping off the wagon causes. This (slipping off) is my biggest problem at the moment, not knowledge thanks to this forum and a lot of testing.
Don't let any of what I've said dampen your enthusiasm, though. You're obviously doing really well in these ctritical early weeks. Build on this with a bit of record keeping and you are well on your way to understanding and control.