Tenses

Hi,

Please take a look at the two paragraphs I've pasted below. They appear near the start of an essay about my fascination with ants. I'm not sure about the tenses in the second paragraph. I start with the past tense and proceed using the present. I don't want to use "would" (But there was once a young girl ... who would) and I want to use the present, but is it ungrammatical?

Originally "But there was once a young girl" was "Contrast that with a young girl." I like "But there..." better, but comments are welcome. Would also appreciate comments on the rest of the paragraphs.

Thanks for your help.

Sarcandra

Excerpt

When tiny orange ants suddenly appeared in our kitchen one day last summer, I felt a jolt of unfamiliarity—what were these things? Ants indoors were rare in the apartment my mother and I shared. They formed a wavy, unbroken line from somewhere outside the window to our garbage pail by the sink, as if they were guests invited to partake of our scraps, confident that their presence would be welcomed. Unmoved, I wiped them off the wall with a damp cloth and put out the garbage.

But there was once a young girl, maybe eight or nine years old, gazing absorbedly at a kitchen wall in a different apartment. Hands clasped behind her back, face thrust towards the narrow ledge formed where the topmost kitchen counter tiles join the wall, she stands for an hour watching a line of small black ants partaking of the food set out for them. She notes the unending queue, the way they greet each other with their antennae, those with a unique size or gait. Abdomens fill out like balloons being inflated as the ants drink condensed milk, and some abdomens become really big and seem ready to pop; gluttony exists even among ants! The girl sometimes places a grain of salt beside some sugar, and is amused to see the ants clamp their jaws around it, then let go and back away the next instant, jaws opening and closing repeatedly as if to get rid of a bad taste.