I suspect many started the same way 🙂
My dad stripped an old freezer and buried it in the garden to make our first fish pond, when I was about 12, after feeling sorry for the ones in the bowl. He went on to build a larger, kidney shaped one. I have a photo of my friend and I swimming (more like wallowing) in it when I was 16 (no I am not posting it here!)
I married at 18 and after a couple of years talked my husband into helping me set up our first tropical tank - we then killed all the fish thanks to incorrect information from the garden centre who sold us the gear (no internet in those days and no local pet shop!). It took a couple of years and many mistakes before we got the hang of it, thanks to helping set up a local fish club then joining the FNZAS.
At the height of our interest, we had 18 aquariums around the house, as our 2 kids had their own tanks in their rooms, and you can find the progress of our pond build (2006 I think) in the cold water section here.
As we are both now retired, we are down to one tropical 4ft tank which has been running since 2000 - 2002. We are considering dismantling it though as we are finding the maintenance harder to do these days and the tank is well overdue to be re-sealed. Every time there is an earthquake I fear the seals will give way!
Our pond, which we enjoyed for about 18 years, was recently filled in to make way for an access ramp for my now disabled husband.
Good luck with your new set-up.