Hi Skippysmom,
My male Siamese Hugo was diagnosed with diabetes when he was 7 1/2. He also gets 2 insulin shots a day and will be turning 15 this summer! Here is my advice:
Make sure to ask you vet as many questions as you need to fully understand what diabetes is about and what the role of insulin is.
If you don't think your vet is giving you the info you need or have other concerns, CHANGE VETS!. I did that 3 times before I found a vet that I had a lot of trust in and was very involved in my cats health.
Diet is a huge factor in a diabetic cats health. If your vet is not recommending a change to prescription cat food (W/D), ask why not. W/D food was the last step in getting Hugo well regulated.
The shots are no big deal. You and the cat will be used to them in a week. When you are not around to give shots (vacation, etc.) get a cat sitter that works at a vets office. A vet tech from your vet's practice is ideal since they are used to shots and know the signs of hypoglycemia and dehydration. Plus if they have any concerns they will usually just take the cat into the office and let the doctors have a look.
The first few weeks are the toughest as you have to adjust insulin levels to get the cat regulated. Make sure you can recognize hypoglycemia (very low blood sugar) and take the appropriate steps. Remember that is always better to err on the side of higher blood sugar than lower.
Here's a good link for some info and a message board:
http://www.felinediabetes.comGood Luck! Hugo and I will be pulling for you.