Damage will be done if your BG levels are above the specified/recommended levels (the actual number varies depending on who you ask) for extended periods.
Well they are going to be important for the rest of your days..
Best kept low and with as few spikes as possible. So you want to aim to be stable and lowish.
Now as to what constitutes "low" that's a whole other question..
Thanks for the advice and the article was interesting (well, the bits I understood) .
It will certainly help me with the suggested self testing routine, which I intend to start next week.