Stay away from her and respect the relationship you share with her. She is your sister and one should not think in such a way for sister. There are plenty of fish in the sea so try for other girls outside the home. If she is hot and sexy then it does not mean that you have a right to have sex with her.
Moreover, she did not send you any hint that she has an attraction towards you and she wants to be intimate with you. She is a virgin and let her be a virgin. Do not make any mistake in the heat of the moment otherwise you would lose your status in family and that would be biggest embarrassing moment for you to face so beware.
However, case would be different if she has approached you for sex but here she did not do anything in that direction so you have to control yourself.
I think you want are interested to catch the target easily without making any effort. She has respect for you, that doesnot mean that you are going to exploit her for sex. You have to mention your age and details background so that your position can b understand in a better way. You have lot of opportunities to involve in physical and emotional relationship with others apart from family members.
It has been observed that people like you exploit the girls in their early teem age and these girls are facing severe psychological consequences in the forthcoming days of their life. The trauma is such a type that change their way of life and sometimes it attract others to exploit further. Don’t take the concept in porn movies into real life. There is sharp distinction in real and virtual life. In case this will come to notice of your family and neighborhood then it would be a awkward situation for you and her.
Suppose she approach you for sex then its your duty to counsel her about its consequences and motivate her to do something that would help her to stay apart from sex with you. These are the basic role of family members at the time requirement. You have to control your desire and dream inside you and try to focus on others. If you are confident and high level desire for sex then you will get chances. Wait for the moment and enjoy the moment with consensus not by exploiting.
It is really a shame that you are asking us for TIPS on trying to seduce your cousin sister. Always build healthy relationships that will stand you in good stead in the future.
As your cousin, she trusts you and allows you to hug and may be even kiss her, but this does not mean that you should take advantage. She has obviously made her stand clear to you and does not intend getting into an incestuous relationship with you. Respect that.
How do you know she is a virgin? Only a doctor who has done a physical examination can tell. But jokes apart, I am sure she doesn't want you to act doctor doctor.
Be more sociable. Get to know more friends. Get a girlfriend and let her play doctor doctor with you.