How to let my girlfriend know I'm ready?

I'm bisexual, and have been dating my girlfriend for a little over three months and we have been best friends for going on two years. We have an amazing relationship despite my parents disapproval and I honestly see myself with her for the rest of my life. Anyways, I have issues with trust and from bad experiences as a child that generally cause me to shake when things get too far sexually. But with her, I dont shake or panic at all. Mainly because we have an incredible bond and incredible trust. I know that she would have sex with me.. except she doesnt believe that I want to. She thinks i want to just to make her happy, which isn't true. I know a few ways to turn her on, like kissing and sucking her neck, etc, but i need tips on how to really turn her on and make her lose control and convince her that I really want yo do this. Any help?