The first computer XT10 4.7Mhz Swan(8088) I build by my self 1983. It actually had Amber monitor then I install CGA card and CGA monitor. It had one 5.25 floppy disk and 20Mb HDD and 640K RAM.

My first that I owned was a Sinclair QL - much enhanced.
I did, however also have an IBM PC XT plus that was supplied by work.

My entry seemed to vanish- however her we go again...
My first computer was an Elliott 405 in 1955 (all valve (vacuum tube..) with delay-line immediate storage and a drum for slower data - followed by 35mm magnetic coated film reels.
(Happy days!)
and my first Microcomputer was an Imsai 8080 (from a kit..) using an Intel 8086 (replaced by Zilog Z80) Teletype I/O and running CP/M ... (later MP/M and CP/Net)
and now,we have Arduino with C...
Gosh!

My first computer was a Commodore Vic-20 followed by a Commodore 64.

The Digicomp was my first computer and the Digicom II was my second. My first electronic computer was the TI 99/4A.

A Telex 80186 PC.

My first computer was an i486sx assembled by Fujitsu. Early 90's. DOS 5.0.

I had used Commodores and Amigas before though, but they weren't mine.

We forgot the most important thing, what would we advise to youths playing with today's innovations, and I am not talking about games but far, far more than that, not even computers.

Here's my advise: playing with Basic on home computers in the eighties did not give me the slightest edge at university, others started at university for the first time and were just as good, maybe better because they had less obsolete stuff taking space in their heads. In the age where everything becomes obsolete so fast it is the people skills that set winners apart, not specific languages or technologies.

Burroughs 205

Memory was a rotating drum about the size of a waste basket, about 4K. All vacuum tube.

Same here, I had the Spectrum+ (for the uninitiated, that's the original 48K board with a better keyboard). I used to love programming that thing but spent most of my time on the vast collection of second-hand games I built up. Funnily enough, I never had trouble loading second-hand games, but had no end of trouble with second-hand peripherals. And don't get me started on bottom-of-the-range cassette manglers players!

I was surprised to read recently that the Speccy's main rival at the time, the C64, only had a 1GHz processor compared to the Spectrum's 3.5 GHz. Commodore instead put the money into a dedicated graphics chip, which the Spectrum lacked - which explains why my friend's C64 games almost all had colourful, side-scrolling graphics, while Spectrum games had all manner of weird and wonderful hacks going on.

I had a Gateway i486 DX2-66 running Windows for Workgroups 3.11. I removed the OS and installed Slackware 2.3.

Radio Shack/Tandy TRS-80 with the 4k ram expansion pack and cassette player/recorder for saving/loading programs!

My first computer was a Video Genie System EG 3003. A copy of Radio Shack TRS-80.
Processor Z80A 1.79MHz 16KB ROM + 16KB RAM, cassette + audio connector to play beeps by writing '1' or '0' in an specific port. I think it was the port 255. POKE(255,0) POKE(255,1) in a loop to make a piii..
Before it I had a Texas instruments Ti58. But I don't consider it a computer.
I have both and still working.

My first computer was a PDP11. I still own the machine.

first computer was a Morrow, back in the late '70s or early 80s
Operating system on one 5-1/4" inch floppy, data on the other. Was more of a word processor than computer. At least for how I used it. Learning to code came later, on a Kaypro PCx86