Sure, I was determined not to fall, but next to them, I was still taking my first steps.
I am not sure what you mean by this.
Armed with the misconception of exploding baking soda volcanoes and Rube Goldberg contraptions, I was blinded by the glamor of a job already completed.
That sentence could be phrased better. It is not clear why those things qualify as misconceptions.
Ending line: To those swarthy teenagers who passed through my exhibit it might remain just a ball of spit, but to me it is yet another dimension of the world my mind can explore.
I think the essay is strong. It shows that you have a sense of intellectual vitality. Though I did think the end was a bit preachy.