First thing first- Definitely take the class and learn the basics.
It is very time consuming for a studio owner to train a person with no experience, so build as many windows and gifts as possible and get a some experience under your belt. Your previous job could be to your advantage. You'll probably pick this up quickly.
Make friends with your local stained glass shops. I'll probably get some disagreement here- but in my opinion (20 years in the industry) stained glass studios are notoriously cagey and nepotistic, so the more they see your friendly face and see that you are serious, the more likely you'll be hired.
Offer to putty windows and do basic repair work. Lots of studios don't like doing it are are more likely to invest time training you if you are willing to do grunt work. You can actually learn a LOT by repairing broken things.
When all else fails- bribe them with cookies. (I've actually been "bribed" and she works for us now. LOL

)