I think letting her control making a plan again is ok. I also think that a simple thing to do is let her it's up to her. She may not know that is your expectation, but at the same time she may be expecting you to respond to her. It's reasonable to think that's her unspoken expectation... I think in her shoes you may expect a response or at least an acknowledgement, yes? Healthy friendships are a dynamic, not a game of who's in control or who's giving more, taking more. Everyone and everything has a balancing point.

I think a simple response back like "these things happen. I hope we can take a walk soon. Let me know when you're free." Is needed. It keeps things light, let's her know you expect her to get in touch with you and that you want to make time to be more than a casual passing acquaintance.

Hoping to give you helpful ideas and perspectives in support of doing things in a new way. Stretching my own comfort zone has been really valuable. I'm so far away now from old patterns and behaviors. I've outgrown them ... or maybe I've moved my comfort zone in a way that makes those old patterns less conformable now. Wishing you the best.