[US] Is this Tax Balance Due real?

Not a part of this sub but I do know of its existence. I haven't checked my PO BOX in a good bit so I went to check today and had a couple letters. In the pile was this letter. Is it actually legitimate or not?

Like its telling me I couldn't pay back **$8** so I owe more. Yeah I know how interest works, it's just the fact that at some point I couldn't pay $8 in April that's bothering me. Like I don't recall getting any sort of notification for this. This was my second time doing taxes so maybe I made a mistake and owed them money for fucking something up? Help would be greatly appreciated as I am a bit gullible and not the smartest money wise