First Pages: YA / Love & Steam & Gasoline

A small, black snowflake landed on my arm, but when I tried to wipe it off, it smeared across my pale skin leaving a thick smudge.

Too. Many. Adjectives.
This is a rookie mistake, and might make some editors stop here. If the whole manuscript is over-adjectived, editing will take far longer than we have time for.

Another reminder of how pale I was. I could hear Aunt Millie now: You should get out more and get some sun. Cooped up in that workshop all day, who do you think is going to marry a skinny, pasty-skinned girl like you?

Marriage. Ha! While all the girls at school worried about marriage, I was worried about the starving people next door and the nearly shot piston on my bike.

Aunt Millie's speech feels trite to me. And while that may be the goal (perhaps Aunt Millie is tragically trite), it's not a good way to start off your manuscript. If this text needs to be here, work on making Aunt Millie's nagging more unique; or perhaps better still, back off from it and let it be reported not as a quote but as a fleeting thought. This girl has better things to think of.

Besides, if your main character's thoughts are really with the people next door and her bicycle, then we should see that. Would she really spend so much time thinking about what other people think she should be thinking? Most people are not quite so meta.

These first paragraphs should introduce us to (and bond us with) her character, not the influences she's clearly not going to be influenced by.

I licked my thumb and rubbed at the black smear again. Dark clouds and even darker snowflakes filled the sky. Up ahead in the city, the factories loomed, making more clouds and sending them onto the horizon. If you got far enough from the city, the snowflakes would eventually turn white.

Huh, I like this paragraph.

I bent down to start the engine on my bike, but a rustle in the bushes next to me made me sit up with my back straight. Aunt Millie would be so proud of my posture right then as she often gets after me for slouching.

No man’s going to marry…

She's still thinking too much about marriage / Aunt Millie to my ear. How brow-beaten is this girl? I would make this "Aunt Millie would be so proud of my posture." and cut the following 15 words. That makes her sound ironic rather than brow-beaten.

The bushes fell silent. I scanned their dark shapes blending into one another. The bare trees stood like sentinels over them. Must’ve been the wind, although I couldn’t remember its chill.

I bent back down to start my bike’s engine when I heard a whirring sound behind me.

"I scanned their dark shapes blending into one another" is a break in voice. Keep up the mood you're creating by making this a more interesting sentence. The rest is intriguing.

I think I would turn the page, but with some foreboding. You've got some good stuff here, but this manuscript promises to be in dire need of editing. Regretfully, no editor has time for "dire".

Roll up your sleeves and (with a good critique group, if you can find one) get started on the revision this manuscript needs before it's submitted.