What you do need is to figure what age group you’re writing to. 

If your main characters are teens that means you need to write to that market. 

This is what they look like:

Childrens - 4 up to 8 years old

Middle Grade - 8-12

YA - 12-18

NA -18 to 30

Adult - 30+

Why is this so important? A couple reasons. First off, you need to cater the story to that age group. If your characters are teens and they’re taking out terrorists or serial killers that’s going to be hard to sell. But if your characters are teenagers and they’re dealing with teenage angst, young love, drugs, violence, mental health, sexuality then that speaks to the people you’re writing for.

It’s also important to know what age you’re writing for because once you do you can write up in order to cross over into multiple markets. What this means is you’re writing for Young Adult, but the subject matter leans towards more adult themes (violence, mental health, murder, etc.) This will draw older people to read your work. Not just New Adult, but adult as well and the more markets you have reading, the more books you’re going to sell.