hello, just to let you know I'm not a professional, just a writer like you.
Over All Sense
I loved it. The flow was going pretty nicely, until you hit the following spots. My suggestions are in ().

Grandma ate another cracker. Velma wondered what kind of animal cracker it was. Were the animal crackers coming to life in her grandma’s tummy? (Put each of these sentences on separate lines. That will keep your flow going smoothly.)

Grandma and Velma pictured the bees wearing tiny boxing gloves. Grandma giggled at the thought of bees in her belly. (Put these sentences onto separate lines.)

Grandma put a handful of animal crackers in her mouth. Velma listened closely. Velma couldn’t hear anything. No angry bees. No musical elephants. No laughing hyenas. Nothing. (Put each on a separate line. Leave out Velma couldn't hear anything.)

Then My final suggestion read it to the age group you were writing it for and see their reactions. This will tell you everything you need to know about your story.
You have a wonderful story and I hope you get it published. Thank your for writing and posting this for me to read. Mystic Angel