Hello,
I am a recent Graduate from National Institute of Fashion Technology, India, one of the best fashion colleges of Asia and have been the academic Topper there and have already designed for casual wear brands like Esprit and Lucky Jeans, which you might be aware of already.
However, as you may be aware, in the Industry, there is a separate pattern making department when it comes to production. A Designer can provide you designs with spec sheets and fabric and trim indications according to the market trend and fashion forecast, not Perfect patterns. I would suggest you to henceforth go ahead and get the designs made into patterns by the pattern master at your production house(or someone suggested by him) because fit is a very important criteria, specially for a Teen market. However, I can guide and assist you with that as well in the process.
Thank you
Hope to hear from you.