If I enlisted in the NG, but now want to go active duty AF, can I do it? How difficult is it and how long will it take?

Since you haven't shipped, it can possibly be done. But bear in mind it's going to take some serious paperwork and prolly get the WTF sneer from your Recruiter

You can do whatever you want until you ship. You are not obligated to go to BMT. If you want to go Active Duty it is a VERY simple process. All you do is tell your recruiter you want to go Active Duty and he will need to DEP discharge you. He may try to convince you otherwise but he has to do it if this is what you want. Let me know if you need any help with the process.

Both of these Warriors are correct its a luck of the draw it depends on the needs of the Air Force and the desire of the Recruiter. If the Air Force has openings they will take you if there arent any the Recruiter gets nothing by putting you in so he wont. You will have to sell yourself to that recruiter.