Do you only have one gear on the back of that bike? Unless all your riding is on the upside of a hill with 8% grade, I'm having trouble understanding why say it's too much for you.
You don't normally ride in the smallest rear cog. Nor do you normally ride in the biggest rear cog. When in either the small front or large front, you really want most of your riding to be in the middle cogs of the rear cassette.
At least that's my opinion and I'm sticking to it.