If it's frustrating, I say cut your losses and get rid of it! :)
Your skills have improved and your taste has changed and maybe you're just not enthusiastic over this any more.
If you still love the fabric, finish the twin and put the rest into the scrap bin. If you're just done with the whole thing, dump it all in the scrap bin or give it to someone who loves it the way you used to. :) No guilt! ;)