Okay, right now you have some puckering.
I prefer to either do a light bonding with fusible web or glue baste with school glue or other water soluble glue. Pins and I don't work all that well together due to my arthritis.
Though you could pin more, use stabilizer, and adjust your stitch. Heck you could even put it in a thin edged embroidery hoop to keep the background flat while you sew.
ali