I'm no expert on felting, but usually an object that will be felted is knit on larger needles, very loosely. The agitation and rubbing together of the fibers causes the felting and shrinkage.
If you knit something tightly, I'm not sure it will felt properly--but I'm pretty sure it will shrink.
You might want to knit a different type flap for this bag and make a different bag for felting. Up to you to decide, though.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry