Aldaniti, you referred to this person as 'vindictive'
I decided to look up the exact definition of the word you used. It came up with two.
[1]
revengeful: disposed to seek revenge or intended for revenge; "more vindictive than jealous love"- Shakespeare; "punishments...essentially vindictive in their nature"- M.R.Cohen
[2]
despiteful: showing malicious ill will and a desire to hurt; motivated by spite; "a despiteful fiend"; "a truly spiteful child"; "a vindictive man will look for occasions for resentment"
Sadly, the only person who appears to come under this category is you.
I would suggest that at every point in most of our lives, we have all felt ill at ease with ourselves. As teenagers, we are not complete human beings. No matter how self assured we may pretend to me, we think we know everything when we don't. Our visions of what's right and wrong are particularly blurred.
Often, we are the product of the people who have brought us up rather than the realisation of what we are. Did you or did you not mention a parent influencing the way in which someone was?
Someone on this thread suggested that you should be nice to people on the way up, because you never know when you might need them on the way down. It never said in that statement that life contains one journey up and one down. You could be up one minute, and down the next. And then up and down again. Snakes and ladders theory you could say. This thread would seem to suggest that the ultimate winner is you. So justice, sweet justice, you might say, eh?! Well forgive me if I don't raise a glass in celebration.
What I would personally advise, as someone far younger than you I would imagine, that it's very easy to take a smug and sanctimonious tone towards someone that has fallen on hard times.
But ask yourself this:
Is the sum total of your existence to be better than those who ruled over you in school. Is life all about oneupmanship? About settling scores that were based on adolescence and all the petty insecurities that go with it.
There are no winners and losers in this. She is obviously some degree of loser for the way in which her life has not turned out in the way she envisaged.
Yet for my mind you are the bigger loser for behaving, as a grown woman, in a matter more befitting of a schoolyard bully laughing at the child who has slipped up and fallen on their arse.