How big was your first tank? Did you have it custom made or did you purchase it from a store/other person?
My first tank was a fairly small one, when I say small I mean big enough for a goldfish to swim in.
I purchased it at a store, let the tank cycle for a few days and went back and bought the goldfish.
I started with what I thought was huge at the time: 39 gallons. That’s funny now that I know people with 120s and larger ?.