You should put a portfolio together of your CAD projects. If you get an interview at a place you will be able to show them the work that you can do. Even though you don't have a certificate let them know you have taken college courses in drafting and you're planning on continuing. I personally don't see why the work you've done in FIRST wouldn't count. Not only does FIRST give/gave you CAD experience but it also shows potential employers you're willing to help out (community service).
We have a CAD department where I work. They're responsible for designing all of the automation systems we build for the plastic injection molding business. 85-90% of the work is done in Solidworks while the remainder is done in AutoCad. I"ll ask some of the engineers tomorrow how they got started and if they have any tips I could pass on to you.
Jason