i mean in my state you cannot under any circumstances have sex under 12 years old
but 13-15 you can IF the other person is within 24 months of your age, although nobody does that because why (i took this info from a government website)(also 16-17 year olds have the 13-15 rule)
so by your definition you can change your sexual organs at age 13, which i think id a good age to make that decision