I had a colostomy reversal. I have never gotten back to the same type of bowel movements--it has been fairly mushy since. Is this normal?

Yes, in most cases. Usually patients with a colostomy have had part of their colon removed. The colon is responsible for reabsorbing water from the stool. If you have less colon, then you will reabsorb less water and your stool will be softer and less formed in character. If you are not having any other symptoms besides the mushy stools, don't be alarmed. See your doctor if you have other symptoms though.
Time will Tell. A colostomy reversal has it's side effects and depending on how much colon was resected, your bowel movements my alter in frequency, consistency, odor, color, etc. Usually, it takes 3-6 months before one can judge how the character of their bowel movements will end up being. Plenty of fluids and fiber in your diet will help by adding bulk to your movements. At least it's great to be normal again!