Tested early and positive .. question?

Edit: alright my mistake to the wrong group, clearly I did it by mistake ... Didn’t realise there was room police on here! Jeeze...

I took a test 4 days before AF.

It was one that says 99% accurate from day of missed period and it was cheap.

So technically took 5 days before I should.

Anyway, it’s positive, which is amazing.

Just wondering, why did it pick it up so early?

Ps I thought I was taking a 6 days earlier one but opened the wrong one as I have about 20 tests in my bathrooms draws lol.