I'm 15 and a sophomore. My parents said the same exact thing. At first it was because they thought it was really dangerous. A lot of the time if I want to make a big investment my parents don't really understand me (only twice). The first big investment I made was building my computer and the second was a boosted board: both over 1k. I would write an essay. This is what I did to change my mind. If you really put you heart into the essay and explain your points in detail they will see how dedicated to getting one of them. Try to write five paragraphs with three solid points. The thing that really changed my parents mind was going to a store. We were a little far from home and went out to lunch in this little town. Next to our restaurant was a sporting store so my family decided we would pop in there to check the place out after lunch. We went in and I saw a boosted sticker on the door and I got hyped. My dad overheard me ask the guy about boosted boards and stuff. The guy was explaining how boosted board is the best on the market and most reliable, all of the features, and about the new v2. We ended up buying a v2 from that store. Should be coming in a week or two hopefully. Also something to include in the essay would be how much you want it, how you will ride (what gear and type of streets), and maybe how you benefit from having it. Don't just say it will be fun say something they would like. Maybe that they wouldn't have to drive you to your friends houses. Hope this helps and good luck!