I get turned on by my sister ?!!?!!!?!?!!?!?

Uh you should probably keep this to yourself because things will get very ackward with everyone. I don't think a therapist would help unless you had raging, possibly violent feelings toward your sister.

I think you should talk to a therapist or your parents or something..

keep it to urself, as long as ur not acting on it, its ok.

She will be disgusted if she found out

Tell her how you feel and see what happens...(;