Today I edited the tag on this question from real-analysis to probability. At present I have low to mid 400 reputation points. According to the privileges sheet I should not be able to do that until I have 500 points. I used an edit link at the bottom of the question. Perhaps this is a bug; perhaps a feature.
This is not a bug. As soon as you'll reach 500 reputation points, you will be able to edit tags autonomously, that is: without approval from a user with higher reputation. Full editing privileges will be granted from 2000 reputation points on.
There's nothing wrong with that, as far as I can tell.