What do you mean when you say a private individual? Someone wealthy? To run their house/personal affairs?
Depends on where you live but there aren't an awful lot of those type of jobs and that's generally not an entry level PA job.
Generally, you will need excellent Microsoft Outlook skills so Word, Excel, Powerpoint, etc. You'll need to know how to create and format business letters, documents, reports, presentations and spreadsheets. A bit of advanced Excel is really helpful so knowing how to work with formulas and pivot tables.
You'll need to be able to manage a constantly shifting diary (or potentially multiple diaries). More often than not you will be managing your own inbox as well as your bosses (and potentially multiple diaries). There's lots of relationship management and you'll need to be assertive. People will tiptoe around the boss but quite happily be as rude as they like to the PA.
A good PA will be anticipating deadlines and prompting decisions rather than waiting for direction from the boss. For example, you'll see an email about an event that will require an overnight stay. Your boss is out of the office so you do the digging of what is required and because you know his preferences and this is something he would generally like to do you, you get a copy of the agenda, find out who is attending and hold a hotel room for that night. It can be a bit more complicated than that but you get the gist!
It's very much an organisational job these days rather than just typing letters and making the tea so if you like working flat out doing 100 things at once then you'll love it.
I have a degree and literally started out doing temp admin jobs and worked my way up to a very senior role which I did for quite a long time. I used to like it but fell out of love with it. Expectations on PAs are horrendous these days and it can be a very stressful job. The last couple of bosses I worked for literally expected me to be on call 24/7.
There are lots of YouTube tutorials for all of the office packages. I would mug up on those and see if you can get any temping jobs to build up some experience. See if you like working in an office before you spend money on Pitman type qualifications. You don't need shorthand!
What appeals to you about it?
What do you think you'll be doing?