may i throw another thought into the mix? first, please do consider a used machine. lots of times people buy them and never really use them. for christmas this past year, i bought my daughter-age 18, a used pfaff hobby 1016 off of ebay. i think, with shipping, i paid $70-. it's not a super fancy machine...but it was a pfaff made in europe and has a wonderful stitch quality to it. from all appearences, the machine was never really used. came with all accessories and attachments that were with it when sold new....
so, i think if you do some careful shopping, you might score a really good deal. and then, if there is any $ left over, maybe your grandparents will put it towards some sewing supplies/fabric/ect. what do you think? and best of luck to you---love hearing about teens sewing. would love for you to post some pics of what you have made!
betsey