My first computer I got for my 6th birthday, however my dad despite being a TV engineer was always too busy to put the plug on, so I had this computer sat there for months that I couldn't use.
Finally at about 7 I thought forget this I'll give it a go, it can't be that hard to put a plug on, just follow the instructions and it should work.
It was then at age 7 I realised how simple electronics is! Live (Brown), Neutral (Blue) and Earth (Green) and how easy it is to wire up a plug - this was something that not even my mum could do, she was really worried I was going to blow up the house or something.
I put the plug on my computer and voila that was my first ever computer.
It was a Sanyo MSX, my dad got it me from the TV firm he worked for at the time, they were selling them cheaper than the British versions like the C64 or Spectrum to try and get their foot hold in the door.
I actually like the MSX it was a good computer, and was very easy to program. The main thing with the MSX was it contained Microsoft Basic (hence the name MSX = Micro Soft X - why do Microsoft like the letter X - MSX => MS X-BOX/MS X-BOX 360)
The only bad thing about the MSX was the actual computer was a flop which was a real shame.
I liked the MSX, and always thought the best things about it was that many of the games were coded in basic and not machine code. So games like Vicious Viper (Snake) and Toshiba Golf could be loaded up then you could press the Break key and have a look at how the code worked, and modify the code for some fun - for example on the Golf game I ended up with things like Blue golf courses instead of green, just by modifying the code slightly. It was great how basic it was and how easy it was to learn different things from it, very much like modern day Open Source programming.
I still have my MSX today, although quite often use an emulator rather than the original machine. It was a very nice computer to use. After the MSX I was given a C64, which I was never overly impressed with, and then a ZX Spectrum, which I always thought that even though it didn't have the same graphics capabilities than the C64 it was far more better, and was easier to program, the C64 you had to get a hefty manual out to find what the basic commands were, where as on the Spectrum they were on the bottom of the keyboard (on the MSX they were on the Function keys).
And then finally I upgraded to the Commodore Amiga - which was amazing, I still prefer the Amiga now to the PC. Workbench was so simple, and entire operating system on one 880k floppy disk as opposed to Windows which takes up nearly 10Gb to do the same thing, and dedicated GPU's and APU's which took PC's many years and a company called 3DFX and Creative to invent.