*PLEASE READ/HELP* Is it ok to let your step sister know you have feelings for her?

Hey, everyone! How's it going? Thanks for taking the time to read and answer my question!

So here's my story. I am a 17 year old teen that lives in a small-medium size town in Washington State. When I was about 4 or 5 years old my parents got divorce. My mom had custody of my brother and I and my dad had visitation rights. After the divorce, my parents dated other people and my mom got remarried when I was 9 in 2005. Also when I was 9, my dad met a woman he really liked. My dad and this woman started dating, and he moved away to live with her about a year after they started dating. The city he moved to was about 70 miles away from the town I lived in. With the visitation rules, he came and picked my brother and I up every-other weekend and we would spend those weekends at his girlfriend's house. Then in 2008 they got married, I was twelve at the time. Both my dad and my step mom have two kids each. Right now the ages of the kids go like this: my step brother(19), my step sister (17), me (17), and my bio brother (14). Ever since I met my step siblings, I liked them. When I was younger, I was close with my step brother. We would hangout all the time on the weekends I was there up until he was about 17 and I was 15, then we started to slowly seperate after he had gained other friends he would hangout with. My step sister's and my relationship is different. It started out that we didn't really care much for each other, as would be expected between a 9 year old boy and a 9 year old girl. But as time went on and it became more natual to talk and interact with the opposite gender, our relationship started to grow. I think I started first noticing that I liked her more than a sister, and that I was attracted to her was when I was about 12 or 13. Since the time we were about 13 or 14 we've been pretty close. This close relationship has only escalated in the past year to where we commonly have deep convesations with each other and share intimite and detailed personal information with each other. I have a feeling that she may already have a clue that I like her more than just a really good sister, but I'm not too sure. In some previous convesations with her, I've picked up on the fact that she really has no idea how an adolescent male's brain works and so it's also a possibility that she really doesn't know. But if I had to bet on one, I'd have to say that I've made enough non-purposeful and subtle hints for her to catch on. Anyways, to my questions. I've been doing a lot of research on if other people have been in these situations, and the resounding answer is "yes". Step siblings having feelings for each other is actually more common than you'd think. With that being said, I was wondering people's opinions on if you think I should come out with my feelings instead of continueing to hide them? I would really like to come out with my feelings, even if she doesn't recipracte. The only thing I'm scared of is if the worst possible thing happens: If she doesn't feel the same way, the situation becomes awkward, she tells the parents, and then who knows what happens next. I really value the relationship we have now and don't want to ruin it, but at the same time, there are feelings that I have that are hard to tie-up and contain. I'm just torn on this guys. Thanks for any and all answers!

P.S.- with your answer, could you also tell me your gender, age, country( if U.S., state too please!), and if a similar situation has ever happened to you. I would just like to know so I know which demographics of people think what. Thanks!