How long does it take for a goldfish to mature?

It takes 2 or 3 months for a houshold pet goldfish to mature, you can tell if it's a female by that time because they will have some white speckles on their lower fins. Plus, though the common goldfish lives for about 2 days in a bowl, but if you get a 10 gallon tank for it and feed it every morning and night until it's mature, then once a day when it's mature, it can live for a long time; I had a goldfish that I cared for ( the pet goldfish not pond goldfish), and it lived for 9 years! ( It just died :( ) But look for red and/or white spots, split fins, or enlarged eyes as these can be deadly but simply buying medicine from the pet store will save your pets life.