Three until I was 9, then Channel 4 was launched.
I remember being awestruck when someone told me that in the USA, they had 20 TV channels including one that showed nothing but children's programmes.
I don't think I would have believed that one day we would have access to hundreds of TV channels, and multiple children's channels. However, I had no concept back then of TV channels that consisted of little more than adverts, or the same programmes repeated several times throughout the day.