Welcome to the forums and congratulations on your new budgies!
Your sky blue pied budgie is a boy and your normal green budgie is a girl.
They are both still very young, they still have most of their baby barring on the forehead, so my guess is they are both around 3 months of age, I'd say your green one is 3 and a half months old while your blue one is a bit younger.
Your new budgies are very cute; I agree with aluz regarding their gender and age.
To familiarize yourself with the forums, please take the time to read through all of the How To Guides, the FAQs and the stickies located at the top of each section of the forum.
You'll find most of your basic questions are answered after you've read through all of them.
Aluz has already answered your questions quite expertly and Deborah has given very informative links for you to look at The only thing I can say is that it's great to have you on the forums and I hope to see more of your gorgeous birds!
Feel free to ask about anything else you may have questions about