I wouldn’t worry about trying to play it at my speed. The thing to remember is: speed comes in time. I would make your goal this: To be able to play it at a certain tempo, steadily throughout the entire piece. So if that’s 70% or 60% of the speed that I played at, then that’s perfectly fine. When you feel comfortable at a certain percentage, bump up the tempo by increments of 5, until you get it to the speed that you want.