I would go anyway. It will be good exercise for you even if you wouldn't ride it through the finish line. Don't give up before you even tried.
Once I went on race called "wiled Sljeme" (Sljeme is the name of a mountain near me) Out of more than 100 people I finished last, but I was thrilled cause I've finished it, and there were many (male!) competitors that have given up. So you see, being last is not always the bad thing. Now I have the experience and I know what to expect for the next time.
Anyway, I wish you all the best
"Life is not measured with the quantity of breaths you take, but with the quantity of moments that took your breath away..."