Why exactly are we expecting Lena to turn evil.
This isn't like that comic where Lana Lang teamed up with Bizarro, who we didn't even see until the end, and poisoned the world with a ring of Kryptonite around it
I am a man with Asperger's Syndrome, so please forgive me if my posting seems weird.

I think Lena is evil and she currently has plans that don't involve her mother or Cadmus. It wouldn't shock me if she's carrying out one of Lex's plans for him.

how old is the Lex actor form smallville anyway? could he portray Lex on this show?

I'm really liking Lena so far. She is awesome. Although I have a feeling she may eventually turn heel and become a villain. In which case, this buildup of her character will make that even more awesome.
I think eventually they'll probably break her and she'll turn to the dark side. Similar to Lex in Smallville