Try plowing through

There are plenty of ways to write.

You can start with the scenes that are clearest in your mind. You can write a scene and edit immediately. You can write chronologically and then decide if the story needs to be broken up in flashbacks and memories.

When you're participating in something like NaNoWriMo and have a word count to meet, you can write however you want, but keep one concept in mind: plow through.

Don't stop to edit. Don't erase a scene to work it over. Don't hesitate.

Write and plow through all your doubts.

Sure, you'll have more editing to do later that way, but you'll reach your word count. And, who knows, you might find a magical story that would never have been if you had hesitated and edited along the way.