Awww they were so tiny when they were babies!
I also managed to make my cacti mortal (to not use the other word which would make me look like a cacti destroyer lol) by overwatering. I noticed they looked fine and had a hole inside. Rotten. Dead. Since then I prefer to water them less often, to protect my babies.
Some shops actually glue fake flowers on the top of the cacti and say they have bloomed. A girl once told me that when she arrived back home she was so proud... And days after... The flower fell down.. The glue wasn't strong enough lol.