As far as the years thing, I will go with what was said in this episode....almost 14 years....why? because the 2 writers of this episode have been with the series from the start. We past 2 earth birthdays with Kara, but only saw the celebration of 1....so, 12+2 = 14.

Hopefully the others writers take note..
Gave this episode a 9/10....well written by 2 of my fav writers from season 1. This episode made me very uncomfortable, which is a good thing, that means the acting was on point enough to make me fidget in the tough scene.
Besides the episode "Changes" I think this was by far one of Chyler's best episodes even though I wanted to punch her in the nose...lol
I haven't said "oh $&*(" this many times in an episode in a long time.
I loved the action, but what did it for me was the enormously tense scenes in this episode. I found myself holding my breath a few times.
The only thing that was sort of a problem for me, and took it down from a 10 to a 9 was the scene in the woods where Kara hears the train and turns for a moment. She has done that now a few times, BIG TIME last week, when she turns her back on Metallo to face Dr. Luthor and at that time I thought.....are you crazy, turn around, the main threat is behind you. But I didn't count off, now that it has happened again, the threat being in front of her and she turns her back on it was a problem for me. But, not a huge one.
So a solid 9 out of 10, really enjoyed this episode, one of my top 5 for the 2 seasons thus far.
It will actually be nice to have that week off after 2 very, very tense episodes. Kind of like the week we had off in between "Falling" and the crossover last season.
"A good teacher is like a candle, it consumes itself to light the way for others"