Tyman, trust me, I know your struggle. I got my first bike at 20. In interest of efficiency, let me provide you this link, so I don't have to type everything over, if you want to read my story: You can read just the first 4 paragraphs if you get bored with the rest of the article -
Winter Riding
However, let me state this. You have a choice in this situation. You have a choice to show your parents you are mature and help out the situation, or to enforce distrust with them if you go behind their backs. Sometimes parents are just unreasonable, like mine were, and you just have to go out and do it. Sometimes, as with Delta's mom, she's very understanding, and Delta's cool about it, so she playes by the rules. It's your call. Depending on which way you want to go, let us know and we'll figure it out, eh?
Also, I highly recommend you take the MSF riding course, and take your parents safety-gear shopping at a local store. Also get a quote on the bike for your dad, with your insurance company, and do as much research as you can.
Motorcycle Safety Foundation has some awesome info.... For helmets, look at HJC DOT and SNELL certified. Try and get a leather jacket with armor, if it's too expensive, a textile jacket with armor.... Riding boots that are comfortable, I can recommend the A-star Harlems (and I think Felix too), and some proper non-designer jeans.... Sorry a bit of a tangent, there's just so much to say.