It's not a big deal, you can apply later, but adsense is not a make or break program, in fact, it pays pennies so not working with it could work in your favor with ALL the other programs out there :)

Thank you so much for your help. They didn't approve of my application. They said: We did not approve your application for the reasons listed below.

Insufficient content:

If you click on Appearance on your Wpress dashboard for your site, you should see an item on the menu called editor.

Click on that and see if you can open the editor. It maybe locked at first

but

If you can open the editor it will be a bunch of html that looks confusing. All you need to do is look to the right hand side of the editor and find the term "head" as instructed by adsense. That's where you can paste the html, but be careful

If you get things wrong when using editor you can mess up the whole site.

If your unsure of doing this - You can message support and ask them to place the html in for you. They are really good and respond quickly