It's to the right of delete, and the left of the time stamp. I don't know why you're not seeing it, but it could be yet another A/B test, I suppose.
We're only allowed to edit our own comments (for obvious reasons), so that's why you're not seeing any "Edit" option below the comments of others.
Norwegian has three genders: neuter, masculine and feminine. (Feminine nouns can take masculine forms.) Each has its own indefinite article:
"Et" is used with neuter words, e.g., et eple, et hus (an apple, a house).
"En" is used with masc/fem nouns, e.g., en bil, en bok.
"Ei" is used with feminine nouns, e.g., ei bok, ei jente.
Anytime you learn a new noun, it's a good idea to learn its gender so that you know which articles, possessives and forms to use with it.