She was housed in a 75 gallon tank with 3 other goldfish. Good food, lots of space, and plenty of water changes will help your baby grow to max potential.
Pearlscales can grow to the baseballs, so your 10g will only last so long as she will need space to swim. The more space you can give her the btter off she will be.
As she gets bigger she will also produce a lot more waste, so water changes will be needed to keep ammonia & nitrIte at 0 and nitrAte less than 20. A filter that moves 10x the amount of water in the tank per hour will help with that. Your filter on you 10g should move 100 gph.
Goldfish are considered coldwater fish, but most fancies aren't as hardy as commons and comets. A heater set to around 76*F will make the more comfortable and active.
Goldies also like company, so if you ever get a bigger tank(at least a 20g) you should get her a buddy. Another pearlscale would be a good choice as they are fat, clumsy, and slow. That way your pearl wouldn't have to compete for food with a faster moving fancy.
If you have any other questions just ask and I will be happy to help.