Hello and welcome to the forums,
Your new budgie is a very cute girl. Did you quarantine her from your current budgie before introducing them, or did you get them together?
Quarantine means housing new budgies away from current birds for about 40 days when you first get them to ensure they are not sick and, if they are, to avoid transmitting diseases to the rest of the birds. Additionally, this gives the new bird time to settle in to their new environment.
Here's a link with more information:
Quarantine IS Necessary!
Most pet shops and unfortunately some breeders too know basically nothing about mutations or gender and often say things to appeal to the customer 😬 There is no such mutation as "fancy rare" in budgies, and there are only a few actually rare mutations which are hardly seen in pet stores. Your girl is very pretty, regardless, and she does have an interesting mutation, which is sky blue yellowface single factor dominant pied opaline
She does appear to be the yellowface II variety; if so, when she moults for the first time, her yellow will spread through her body and make her a pretty greenish color
Is this your first time owning budgies?
It's great to have you on the forums and you've come to a great place to learn even more about the best of budgie care practices. Please be sure to read through the forums' many other budgie articles and stickies! I've put a few to get you started down here as well. If you have any questions after reading through things, be sure to ask as we'd love to help!
Essentials to a Great Cage
A Healthy Diet for your Budgie
Hope to see you around and hear updates on your budgies!