For me, my longterm love affair with guinea-pigs started at school. I was 8yo. My teacher had a guinea-pig who was alone in the day so she brought the pig and the cage into school.
Then over weekends we were allowed to (with parental input) to ask to take her home.
When we moved from that town to a house with a garden, my first Christmas present was............my guinea-pig (this was 1975)
Quickly followed by my brothers guinea-pig (two girls we were told) followed a few weeks later by an unexpected litter.
Over the years we added as they went to The Bridge.
Then , years later I had my own 9yo DD who wanted a pet.
We got the first of our hogs, lardy rescue boars.
Currantly we have GP4 GP5 GP6 (after GP2 died,we got GP3)
I keep telling myself and DH that these will be The Last......but I said that about the sows then suggested the new boar (who is GP6)
I reckon we'll be mad piggie people when we're 90! 
They can thank or blame Snowy, the Classroom Piggie.