The fact that you do not use a computer now does not mean you won't be required to use one in the future. Information technology is a central component of modern work, and few roles in today's working environment escape its impact.
You could ask your work colleagues whether they have been requested to undergo the same training and if they have, whether they have done it and what their experiences were. You might discover that it wasn't that bad. You must not lose sight of the fact that it will add to your own skillset.
Keeping your skills up to date is vital during a recession, with so many employers making redundancies. In practice, those with the widest range of skills are most likely to hold onto their jobs. And if you find yourself being made redundant and having to re-enter the jobs market, you will be glad of the extra skills and training as it might help you access a new job.
There may be a union learning rep at your workplace who can talk to you about training if you are unsure. You should also take a look at the resources on the Unionlearn website. These will help you find the kind of skills training that is right for you and then you can discuss it with your employer.