Hello, Maria, and

!
Don't worry too much about coloration - 3 months is a rather young age for them to show their true color. Some fish take up to a year for that. Mine are now 4 months old, and just now have gone from the olive/blackish color to whatever color they are supposed to be by genetics. And even then - over the years, you'll see many more color changes to come.
Got some pictures of the little ones? We always love to see pictures - kind of like baby pictures for any new parent. What are they housed in, and what are you currently feeding them?