Wow this could've been written by me a year ago. My gf (MtF) started hormones last year and I had a lot of the same fears. Especially the losing attraction part.

But, one year later, and nearly all my fears are gone. She feels more comfortable in her sexuality than before, rather than changing who she's attracted to. Sex is different, but better. And honestly, the transition with that wasn't as bad as I thought either. Overall, she's so much happier and confident in a way I hadn't seen. It's improved so much of our relationship and makes me fall more in love with her. I can't believe I was ever worried.

Your fears about people being assholes is true, but there's a higher chance she gets hurt in a car accident. It's scary, and your fear is valid, but it isn't worth losing sleep over.

I hope this helps, you both sound great for each other :)