Steven was trying to get better with his Diamond powers. And before left Beach City (Steven isn't in this) Steven accidentally creates a Lapis Lazuli gem(you). gave to Pearl to take care of not knowing if you create a physical form.

All of the Gem's new of you. Well they knew of the gym Steven created so they took care of you.

Garnet I already knowing the outcome because of sapphire refuses to tell anyone anything. Pearl being a perfectionist trying to get you the form of body. Amethyst got bored at the second day. Lapis got curious about another lapis lazuli(you). And Paradox trying to get you the formal party as well.

One day you finally do forms taking Everyone by surprise when you finally form in the middle of the living room. The first ever male gem from a full female species.