I have 80 ewes. I started shearing 2 years ago. I'm 41. Bearing all this in mind, and I don't know how close this relates to your situation, this is my advice.
Buy a sheering machine, handpiece, combs and cutters. The 12v Horner set up is very good. But if I had my time again I'd spend the extra £100 or so and get a mains set up. Lifting a battery from the car is a pain, because when you start 10 ewes in a session will exhaust you. So the battery will be in and out, and that gets tedious.
Buy the Wool Board intro DVD Horners sell that too (there are some good instructional clips on YouTube, but I cant find the best ones just now). There is also a good guide on YouTube here.
Watch the DVD a couple of times. Don't worry too much about the cutting. Cutting is easy. Worry about feet position. Worry about what you are doing with your knees.
Set up your kit. Get 3 or 4 ewes in one night.
Watch your DVD again in the morning. Then one more time and concentrate on the first few moves. Sheering the belly and first leg.
Go out and try it. It'll be hard and you might nick the belly, and you'll feel bad.
Put the ewe down. Give her a rest. Give you a rest. Watch the next couple of moves on your DVD. Take your time. Go back to the ewe and try that.
You can find step by step pictures on the internet. Where to stand. The direction of the cutting blows. They might not match the Wool Board DVD exactly but they'll be close. Print them out and pin them near where you shear to refer to.
If you sheer 4 ewes on your first day be happy.
You'll get better.
The following year book yourself on a shearing course. You'll know roughly what you're doing and the instructor will help you get better and you'll remember what he says. If you go on a course having never sheared you'll walk away after 2 days barely able to stand and you won't be much cop at shearing. Every move will be new to you and because it's new it'll be exhausting and you won't end up shearing many ewes and you won't get much practice.