Congrats on the card!! I would probably die if I got that kind of SL (but I know it's normal for a lot of people)
As for the late payment, I am kind of interested that you were able to get the card only one month after the late payment. I had a returned payment on my CapOne card (not a late, I had already paid it twice that month) and when I tried to get a CLI they denied me because of a recently returned payment. That reason didn't go away for 3 whole months, and then they found another reason to deny my CLI.