I am fairly old too, but I was using the Tandy computers back when there was no such thing as a mouse or clicking on something. We had to type in instructions for the computer in Microsoft Basic Computer Language, which you had to learn in order to operate a computer. Later the Tandy 1000 were running DOS and had floppy disk drives. About the same time the Internet started up, I started experimenting with Linux. At that time the commands had to be typed into the terminal and it was very unforgiving of typing or spacing errors. The terminal still is, and comes included with any Linux personal computer operating system. The later versions of most Linux Operating Systems also have a point and click interface, much like the Windows OS. Most of the basic functions can be controled with a mouse click now, but the terminal program is still there to allow over-ride or intiate commands that are not included in the point and click programming.
Linux has hundreds of different versions, called Distros (for distributions) Each Distro can have as many as 30 or 40 different versions. Nobody needs to know all about every one of them, or what they do. Each version is created and aligned to be very good at certain things and still have the basic functions of a personal computer included. Some versions are specialized to do Graphics, Photo Editing, Digital Animation, Art, and other graphic funcions. Other Linux versions are best at Audio and Video Editing, making movies, editing your own video, etc. Some versions are best at security, having more options for firewalls, locking down networks, and keeping the system secure. Some versions of Linux are specialized for other specific tasks. All will do the basic stuff like Windows does, and using about 20% of the RAM and ROM that Windows needs .
You only need to know a little about the particular version you choose. You learn as you go, and nobody knows everything about all the Linux Distros. To start with, I was just using old computers that people gave me to try the Linux Systems. When their computers were too old to run the latest version of Windows, they brought them to me to get all their pictures, songs, and documents off of the hard drive and load it into the new Windows computer they bought. Most of them had no use for the old Windows computer , which was too slow to do much on the web, but with Linux loaded on it, the old computer was as fast as the new Windows machine they just bought. They gave me the old computers in exchange for migrating all their pictures and papers to their new computer. I would load different versions of Linux on them and try new operating systems. Currently have 5 or 6 computers that will operate and 3 of them are dual OS, one has a Solid State Drive, faster than anything you ever seen. The Linux computer I use on the web is an old Hewlet Packard about 15 years old.
The best thing about Linux, it is basically free. The disks you can get from computer stores or off the Internet have a minimal charge, usually less than $20 which is to help cover the cost of the thumb drives and shipping. The Linux Operting System is free. You can actually download an entire Linux OS off the web and install it for no money at all.