Well done! My first century was "accidental" -- I was on my first long tour and hadn't planned to ride such a long way on this particular day, but I had a tailwind, felt good and accommodation was a bit sparse where I was.

I was beat at the end, but I felt good as in satisfied, and, of course, it lives long in my memory, as I am sure yours will. I've lost count of the actual number of done since, but it's around 100, I think.