Dustin has taken the time to give you useful advice. He has some good suggestions.

It might be noted, however, that "pasty white guy" has become somewhat of an archetype, and when you see the words you get the image: a bit pudgy, doesn't see much sun ever, probably not very athletic. Pasty and white might seem redundant, but actually just "pasty" sounds odd, mostly because we never hear anyone described that way unless it's "pasty white guy", or some variation of that.

I'm not really sure what "works alone" means here. He's not alone and Lashay quickly enters the picture. He's doing his task alone, but doesn't everyone in a kitchen?

Dustin's suggestion is good, other than pasty by itself seeming odd.

Could there also be a chance to add some color to this? You have to be careful about that in screenwriting. Extra words can piss some readers off.

For example:

A young pasty-white dude simultaneously assembles two Whoppers and an Original Chicken Sandwich like it's an Olympic event. Meet, DAVID, 24, a creature of fast food in more ways than one.

Not saying that's good, but you get the idea.

First, I like that you used "assembles". Excellent word. I also love the specificity of "Original Chicken sandwich".

Dustin begins with the character name. That IS the method we all use more often. But is it a mistake?

Sean starts out with character description. Here's why I like it better: it's an image. The name David  is just a name. Beginning first with the image brings me into the scene. I see a pudgy dude making burgers like it's a competition. THEN I learn his name.

You could say:

A pasty-white dude, DAVID, 24, assembles fast food sandwiches like a madman.

That might be the most efficient way. Probably the safest.

Should a writer take a chance and sometimes color it up? Probably. The problem is most of us are not really good enough to do it in a way that's more entertaining than annoying. I don't myself attempt much of that in screen, I'm not good enough. I've seen Dena and Dave do it to positive effect, however. And I've seen pro writers do it to stand out.

It is not a mistake to start a line with a character name. It is only a mistake if you do it too often. I also prefer to use a writers own words when I rewrite sentences, it's less insulting.

It's not a mistake. It just works better to begin with the image then add the name. Picture worth a thousand words.

Quoted from leitskev It's not a mistake. It just works better to begin with the image then add the name. Picture worth a thousand words.

It doesn't work better either. What works better is to mix it up throughout the writing. A character is an image too not just a name. It is perfectly fine to start with a character as an image just as it is to start with a building or a field.