How would i know if someone wants sex with you?

[Stephen]

How i mean by that is, i have a best friend (girl) . now i know you are all going to say its wrong to have sex with your friend, but we both really like each other. We became friends, and not bf/gf as i took too long in asking her out, but will ask her out soon, and see what she says. Now the main point, she told me a few weeks ago that she wouldnt mind kissing me, i said are you sure you want your/my first kiss to be with me. She said sure, why not. Then before that she said she wouldnt mind sleeping in the same bed as me. What im trying to say is, if we were to kiss , and she wanted to take it further, how would i know, i dont want to make her do something she doesnt, and make her hate me for it. I told her i would do anything with/for her , and said if i were to go too far then she was to only say stop and i would. I respect her a lot and am in love with her i cant help it, she knows i like her a lot too. If we were to sleep together , or if we were close and we kissed, how would i know if she wanted more,when we are close i would tell her i reeally like her a lot. But how would i know if she wanted more from me? would she give signs or would she try to undress me or her ? Obviously i like her a lot and would want to have sex with her, but wouldnt want to make her dislike me for taking it too far with her. Please dont say 'dont do it, things will never be the same, it will be akward in the future etc' I like her more than a friend and she knows this. Maximum points if yu can give the best answer.