The first thing I would suggest is to stop avoiding relationships. Even one with a kinky side is only as a good as the dynamic between the two partners.

Second, if you feel that she doesn't like the sound of your ideas but stays with you, back up, let it go for a while. You are young (or so you sound in your posting) and have plenty of time. Don't spoil things by coming on too strong. After a time, ask again in a different way.

I am talking to my wife about bondage and she gave me an absolute no right off. After a time I came back and told her I wasn't looking to put her in chains and beat the crap out of her, but that is what she thought. No, I said. What I would like to do is to tie you to our bed, not uncomfortably, with soft smooth ropes, and kiss and cuddle and stroke you. You would not be in any position to kiss cuddle or stroke back, you would just be like a sponge soaking up all my affections. I will slowly build your arousal until you feel like you cannot stand it anymore. Then, when I let you cum, it will be the biggest explosion of your life. It will be like fires, and fountains, and flowers. I want to have to peel you off the ceiling, or have you floating in the clouds. I want you to be wobbly in the knees. I want it to be an hour before you stop moaning.

As I told her this I got more and more excited myself. She saw that and didn't say no this time, and she is thinking it over. Soon I will ask again.

Sometimes we forget to let our partner know what's in it for them. We look selfish, even predatory. Remember it is a relationship not a dictatorship. Maybe even suggest that she can do the same for you. You said you are dominant. "I guess." Maybe you aren't. Maybe you are a switch. Maybe not. Take the time to find out.

Explore. Don't rush. Have fun.