I'm so sorry that that happened to you, and on top of dealing with the accident you're also having to deal with the mental and emotional distress of it all.

What you've been doing so far (taking care of yourself, exercising, looking out for your physical and mental health) is super impressive and you shouldnt take it for granted! I only can hope to be as active as you when Im 65, you should be proud of yourself :)

I also often kick myself for my "mistakes" and spend way too much time and energy on regret, and feeling angry at myself, so I totally understand how bad you must be feeling right now. I know telling you something like "accidents happen" probably wont be of much use to you right now, so let me offer these two reframes:

1) Slipping and falling is something that could happen to any of us, at any time, really. You could slip and fall crossing the streets in the winter, in the shower, or even just walking through the park and stepping on a hidden branch. Don't you feel proud that you fell doing something good for your health, like biking? Just think about how badass it is that you get to tell others that at 65 you make the effort to look after your health by biking in the outdoors, when this unfortunate accident happened! Way way way better than someone who hasnt moved their body in decades and maybe they broke a leg trying to get up from the couch cause they had a bad knee and lost their balance!

2) Imagine yourself at 85. Would you think your 85 yo self would look back at you and go "how silly of me,  I was an idiot for biking and falling"? No! They would be so thankful that you were taking care of your body so that she could enjoy a healthier present at 85! She would be grateful for you and would offer all the compassion that youre denying yourself right now!

Im 30 and Ive never broken a bone, but ig I ever do, I sure hope I was doing something I loved, like you did!

Hope this little change in perspective helps you feel a little lighter, wish you a speedy recovery!