Agree with JS!
I adopted Sweep - a diabetic cat, a couple of years back.
It's completely overwhelming at first, and although it's a good idea to read about the condition as much as you can, I would get a handle on the basics and injections first.
I'm afraid I haven't had any experience of injecting a nervous cat: Sweep is a big bruiser and you have to be very firm with him!
Don't worry if it takes a while to get the knack. Thoughts that we were never going to get the hang of it/that we were hurting him, shaky hands and tears are all par for the course! Very occasionally, one of us still pricks a finger, or ends up running around the room chasing a cat with a syringe stuck in it's scruff because we weren't quick enough to push the plunger!
But don't fret - at the end of the day, injecting a cat is far, far, easier, and less stressful I think (for both parties), than pilling one!
Feel free to PM/contact me on Facebook if you would like to share/ask anything.
Jas
xx