Well, this is a tough situation.
Answer this question:
A person who you are not interested in asks you out. Do you?
A) Pretend to like that person, in an attempt to spare that person's feelings.
B) Be honest, and tell the person how you feel in a calm and mature way
C) You rudely turn down her offer, not caring about how they feel.
Answering that question could be an outlet.. -OR-
You could do the obvious, mature thing for this type of situation: you could tell Steph how you feel, sparing her feelings where you can, but still telling her the obvious; that you're not interested, but don't walk up to her and change your decision because you are scared of hurting her...in this situation, you have to do what is right for you.
As in any relationship case, you have to follow your instincts; your emotions; your heart.
PM me if you need to talk.....I am always listening.