I had my female spayed at age 2 1/2. I did opt for the pre-surgical bloodwork because we had just brought her home and she is a breed that can run an abnormal liver enzyme. The blood work also is a guideline to see if the dog has any possible unseen liver or kidney problems that could cause them to not process the anesthesia normally. It isn't a requirement at my vet until the dog is a senior, but you will sign many, many papers if you refuse the blood panel. My pup will be neutered this summer around one year. I will opt for the blood panel for him as well. I wasn't offered fluids, but believe this was listed in the paper work as being given on an as needed basis, and I signed approval for this as well. She didn't get fluids.
Personally, I feel more comfortable getting the bloodwork and would opt for that. If I were undergoing surgery, I would want it for myself. I know that when I called to check the spay prices I was told there were price differences based on the weight of the dog. In my case the change started at 30 pounds, so my dog, even as an adult, fell in the lower category.
Wishing a speedy recovery. Try not to worry (I know that is very hard).