If you want the project to be exactly as the pattern then, yes, ripping it all out and reworking in the correct stitch is the only solution here.
However, as the others have said, it looks lovely and there is nothing wrong with adding your own design features such as a section in a different stitch pattern.
The outer edge of this fabric is in garter, this is knit every row, right side and wrong side. The result is a line of waves with a gap between, if you stretch it out the waves part and a row of Vs can be seen between the rows of purl bumps.
The main fabric is stockinette, rows and columns of V shapes. This is knit on the right side row and purl on the wrong side row.
The stripe or section of a different texture is called reverse stockinette. It is made by purling on the right side and knitting on the wrong side. Purls look like bumps or lines across. It is more closely packed than garter stitch.
As you become more experienced you will easily recognise the difference between the knits and purls. For this piece if you are looking at knits, Vs, then knit that row. If you are looking st purls, bumps, then purl that row.
With a more complex pattern it can help to put a stitch marker or bit of yarn on the right side of the fabric to help remind you which side is which.
Your knitting is lovely and even and so neat!
I would leave the purled section as a design feature and either do the rest in plain knit with the garter boarder, or do another panel of reverse stockinette later on.