Idea of marriage sinking in

I forgot if I mentioned here but I've been engaged for over a year now. Nothing fancy, we just talked about moving in together and decided we might as well get married too. I've now been to two weddings since that day and the last one (it was my baby-sitter's wedding) really brought things home for me. For a while I just saw it as a huge party with a focus on me and my SO (actually more me), having fun thinking about what it will be like, what dress I will wear etc... But seeing my old friend get married made me think a bit deeper. It means I will be with this person, if not the rest of my life then hopefully a very long time till one of us dies. Having BPD makes it hard to conceptualize and stick to commitments so this idea scares me and at the same time is desirable. I'm not very good at visualizing the future and sometimes I worry, will I ever get sick of him? But I've been told by a very wise person that true love is not a feeling, it is a choice. Choosing to commit. That sounds like you have to be a really strong person to truly love and I don't think I am strong at all. But God has been changing me like crazy so hopefully our love will become stronger as we age. Scared as I am, I can't picture myself with anyone else. I guess there isn't that much mystery around choosing your life partner. You just choose when you feel the time is right. And if for some reason it turns out to be a bad choice, I will have learned a lot. Win-win either way.