You CAN get there! I live at the top of a hill that's roughly that (I think it might actually be 16%?). The first 2 times I did it, I just tried to get as far as I could, and then I walked. I think the first time I made it about 1/3 of the way, and the second time, about halfway. I can now get there, albeit extremely slowly (sometimes I'm amazed at how I'm still upright, I'm going so slow).

What kind of gearing do you have? I have a triple and I get in to the absolute granny gear of the granny ring to make it up the hill. Another thing that seems to help me is that the hill has certain landmarks that I used to push myself with. The first time, I told myself I could get to the fire hydrant. Then, I wanted to get to the sign that was the next "landmark" beyond it. I found that having a goal like that helped break it down into more manageable parts and made it feel less overwhelming.