First bike ever ridden at 12 was an old 72 Honda 125. Had a hillarious accidental ride through a freshly plowed garden where whenever I hit a rut my hand (in death grip) would pull hard down on the throttle and bounced thru the garden. Everyone was rolling on the ground it so funny.

Wish I had a video of that one.
My first bike ever owned when I was 14 was a 78 Honda XL250 Enduro. Paid half with my brother and bought from uncle.
Stupid squid brother trashed it the first week we got it. Came into the house with scrapes and blood with his pants torn from the shin to the thigh. All he said was, "I crashed." Broke the clutch bracket, destroyed the headlight assembly and put a huge dent in the gas tank. Dumb A#$ Didn't even pay for the damages.
After it was fixed, enjoyed every minute on that bike riding at an abandoned quarry.
2nd bike was an 83 Honda Nighthawk 450. Fun bike, but way underpowered.